replace deprecated optparse with argparse

following guidelines from:
https://docs.python.org/2/library/argparse.html#upgrading-optparse-code
except, still using option = parse.parse_args() instead of args = ...

- using the following script in folder fdroidserver:
	for i in *.py; do
		sed -i -e 's/optparse/argparse/' \
			-e 's/OptionParser/ArgumentParser/' \
			-e 's/OptionError/ArgumentError/' \
			-e 's/add_option/add_argument/' \
			-e 's/(options, args) = parser/options = parser/' \
			-e 's/options, args = parser/options = parser/' \
			-e 's/Usage: %prog/%(prog)s/' $i;
	done
- use ArgumentParser argument to replace (option, args) = parser.parse()
  call
- use parser.error(msg) instead of raise ArgumentException as suggested
  in https://docs.python.org/2/library/argparse.html#exiting-methods
- in fdroid catch ArgumentError instead of OptionError

fdroidserver/readmeta.py

@@ -17,18 +17,18 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from optparse import OptionParser
+from argparse import ArgumentParser
 import common
 import metadata
 
 
 def main():
 
-    parser = OptionParser(usage="Usage: %prog")
-    parser.add_option("-v", "--verbose", action="store_true", default=False,
-                      help="Spew out even more information than normal")
-    parser.add_option("-q", "--quiet", action="store_true", default=False,
-                      help="Restrict output to warnings and errors")
+    parser = ArgumentParser(usage="%(prog)s")
+    parser.add_argument("-v", "--verbose", action="store_true", default=False,
+                        help="Spew out even more information than normal")
+    parser.add_argument("-q", "--quiet", action="store_true", default=False,
+                        help="Restrict output to warnings and errors")
     parser.parse_args()
     common.read_config(None)