buildserver: trim pre-installed NDK list down to the bare minimum

This keeps the Long Term Support release and the latest release installed.
r10e was kept in because it needs a special extraction method, since it is
a .bin file, not a .zip.  r12b is kept in because it is the old default.
Here is a survey of the NDK versions used in the most recent Builds entry
in each app that uses the NDK:

{'r10e': 6,
 'r12b': 93,
 'r13b': 4,
 'r14b': 5,
 'r15c': 7,
 'r16b': 14,
 'r17b': 4,
 'r17c': 7,
 'r18b': 9,
 'r19c': 17,
 'r20': 1,
 'r20b': 22,
 'r21': 3,
 'r21d': 56,
 'r21e': 65,
 'r22': 9,
 'r22b': 15,
 'r9b': 1}

#517


import glob
import os
import yaml

try:
    from yaml import CSafeLoader as SafeLoader
except ImportError:
    from yaml import SafeLoader

ndks = dict()
for f in glob.glob('metadata/*.yml'):
    with open(f) as fp:
        app = yaml.load(fp, Loader=SafeLoader)
        if app.get('Disable'):
            continue
        build = app.get('Builds', [])[-1]
        if build.get('disabled'):
            continue
        ndk = build.get('ndk')
        if ndk and ndk[1] == '9':
            print(f, build)
        elif ndk and int(ndk[2:3]) < 18:
            print(f, build)
        if ndk:
            print(f, ndk)
            if ndk not in ndks:
                ndks[ndk] = 0
            ndks[ndk] += 1

import pprint

pprint.pprint(ndks)

buildserver/config.buildserver.yml

@@ -1,16 +1,6 @@
 sdk_path: /home/vagrant/android-sdk
 ndk_paths:
   r10e: /home/vagrant/android-ndk/r10e
-  r11c: /home/vagrant/android-ndk/r11c
-  r12b: /home/vagrant/android-ndk/r12b
-  r13b: /home/vagrant/android-ndk/r13b
-  r14b: /home/vagrant/android-ndk/r14b
-  r15c: /home/vagrant/android-ndk/r15c
-  r16b: /home/vagrant/android-ndk/r16b
-  r17c: /home/vagrant/android-ndk/r17c
-  r18b: /home/vagrant/android-ndk/r18b
-  r19c: /home/vagrant/android-ndk/r19c
-  r20b: /home/vagrant/android-ndk/r20b
   r21e: /home/vagrant/android-ndk/r21e
   r22b: /home/vagrant/android-ndk/r22b
 

buildserver/provision-android-ndk

@@ -15,7 +15,7 @@ if [ ! -e $NDK_BASE/r10e ]; then
     mv android-ndk-r10e r10e
 fi
 
-for version in r11c r12b r13b r14b r15c r16b r17c r18b r19c r20b r21e r22b; do
+for version in r21e r22b; do
     if [ ! -e ${NDK_BASE}/${version} ]; then
         unzip /vagrant/cache/android-ndk-${version}-linux-x86_64.zip > /dev/null
         mv android-ndk-${version} ${version}

makebuildserver

@@ -293,26 +293,6 @@ CACHE_FILES = [
      '0e46229820205440b48a5501122002842b82886e76af35f0f3a069243dca4b3c'),
     ('https://dl.google.com/android/ndk/android-ndk-r10e-linux-x86_64.bin',
      '102d6723f67ff1384330d12c45854315d6452d6510286f4e5891e00a5a8f1d5a'),
-    ('https://dl.google.com/android/repository/android-ndk-r11c-linux-x86_64.zip',
-     'ba85dbe4d370e4de567222f73a3e034d85fc3011b3cbd90697f3e8dcace3ad94'),
-    ('https://dl.google.com/android/repository/android-ndk-r12b-linux-x86_64.zip',
-     'eafae2d614e5475a3bcfd7c5f201db5b963cc1290ee3e8ae791ff0c66757781e'),
-    ('https://dl.google.com/android/repository/android-ndk-r13b-linux-x86_64.zip',
-     '3524d7f8fca6dc0d8e7073a7ab7f76888780a22841a6641927123146c3ffd29c'),
-    ('https://dl.google.com/android/repository/android-ndk-r14b-linux-x86_64.zip',
-     '0ecc2017802924cf81fffc0f51d342e3e69de6343da892ac9fa1cd79bc106024'),
-    ('https://dl.google.com/android/repository/android-ndk-r15c-linux-x86_64.zip',
-     'f01788946733bf6294a36727b99366a18369904eb068a599dde8cca2c1d2ba3c'),
-    ('https://dl.google.com/android/repository/android-ndk-r16b-linux-x86_64.zip',
-     'bcdea4f5353773b2ffa85b5a9a2ae35544ce88ec5b507301d8cf6a76b765d901'),
-    ('https://dl.google.com/android/repository/android-ndk-r17c-linux-x86_64.zip',
-     '3f541adbd0330a9205ba12697f6d04ec90752c53d6b622101a2a8a856e816589'),
-    ('https://dl.google.com/android/repository/android-ndk-r18b-linux-x86_64.zip',
-     '4f61cbe4bbf6406aa5ef2ae871def78010eed6271af72de83f8bd0b07a9fd3fd'),
-    ('https://dl.google.com/android/repository/android-ndk-r19c-linux-x86_64.zip',
-     '4c62514ec9c2309315fd84da6d52465651cdb68605058f231f1e480fcf2692e1'),
-    ('https://dl.google.com/android/repository/android-ndk-r20b-linux-x86_64.zip',
-     '8381c440fe61fcbb01e209211ac01b519cd6adf51ab1c2281d5daad6ca4c8c8c'),
     ('https://dl.google.com/android/repository/android-ndk-r21e-linux-x86_64.zip',
      'ad7ce5467e18d40050dc51b8e7affc3e635c85bd8c59be62de32352328ed467e'),
     ('https://dl.google.com/android/repository/android-ndk-r22b-linux-x86_64.zip',