buildserver: unpack gradle versions with provisioning shell script

This was not using anything special from chef, so do it in a shell script
instead.  This makes the script easier for the python/shell people, and
probably uses less memory, since chef is a memory hog.  This might even
make the provision go faster since it uploads the whole script as a file to
the VM, then runs it there.  I think chef sends each command via SSH.

buildserver/gradle

@@ -0,0 +1,80 @@
+#!/bin/bash
+
+bindir="$(dirname $0)"
+basedir="$(dirname $bindir)"
+verdir="${basedir}/versions"
+args=("$@")
+
+v_all=($(cd "${verdir}" && ls | sort -rV))
+echo "Available gradle versions: ${v_all[@]}"
+
+run_gradle() {
+	"${verdir}/${v_found}/bin/gradle" "${args[@]}"
+	exit $?
+}
+
+contains() {
+	local e
+	for e in $2; do
+		[[ $e == $1 ]] && return 0;
+	done
+	return 1
+}
+
+# key-value pairs of what gradle version each gradle plugin version
+# should accept
+d_plugin_k=( 2.1  2.0 1.5 1.3 1.2   1.1   1.0 0.14 0.13 0.12 0.11 0.10  0.9  0.8 0.7 0.6 0.5 0.4 0.3 0.2)
+d_plugin_v=(2.12 2.12 2.4 2.4 2.3 2.2.1 2.2.1  2.1  2.1 1.12 1.12 1.12 1.11 1.10 1.9 1.8 1.6 1.6 1.4 1.4)
+
+# All gradle versions we know about
+plugin_v=(2.13 2.12 2.11 2.10 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2.1 2.1 1.12 1.11 1.10 1.9 1.8 1.7 1.6 1.4)
+
+# Find the highest version available
+for v in ${plugin_v[*]}; do
+	if contains $v "${v_all[*]}"; then
+		v_def=$v
+		break
+	fi
+done
+
+# Earliest takes priority
+for f in build.gradle ../build.gradle; do
+	[[ -f $f ]] || continue
+	while read l; do
+		if [[ -z "$plugin_pver" && $l == *'com.android.tools.build:gradle:'* ]]; then
+			plugin_pver=$(echo -n "$l" | sed "s/.*com.android.tools.build:gradle:\\([0-9\\.\\+]\\+\\).*/\\1/")
+		elif [[ -z "$wrapper_ver" && $l == *'gradleVersion = '* ]]; then
+			wrapper_ver=$(echo -n "$l" | sed "s/.*gradleVersion *=* *[\"']\\([0-9\\.]\\+\\)[\"'].*/\\1/")
+		fi
+	done < $f
+done
+
+if [[ -n $wrapper_ver ]]; then
+	v_found=$wrapper_ver
+	echo "Found $v_found via gradleVersion"
+	run_gradle
+fi
+
+if [[ -n $plugin_pver ]]; then
+	i=0
+	match=false
+	for k in ${d_plugin_k[@]}; do
+		if [[ $plugin_pver == ${k}* ]]; then
+			plugin_ver=${d_plugin_v[$i]}
+			match=true
+			break
+		fi
+		let i++
+	done
+	if $match; then
+		v_found=$plugin_ver
+		echo "Found $v_found via gradle plugin version $k"
+	fi
+fi
+
+if [[ -z $v_found ]]; then
+	echo "No suitable gradle version found - defaulting to $v_def"
+	v_found=$v_def
+fi
+
+run_gradle