have --version ONLY print the version number

Make --version much less verbose and only print out the version number
to facilitate easy parsing by scripts. We don't really need the verbose
copyright output, it is show with --help anyway.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

Changelog.draft.rst

@@ -16,6 +16,8 @@ New Features
 Changes
 -------
 
+* have --version ONLY print the version number
+
 Bug Fixes
 ---------
 

offlineimap/init.py

@@ -60,7 +60,7 @@ class OfflineImap:
     def run(self):
         """Parse the commandline and invoke everything"""
 
-        parser = OptionParser(version=offlineimap.banner,
+        parser = OptionParser(version=offlineimap.__version__,
                               description="%s.\n\n%s" % 
                               (offlineimap.__copyright__,
                                offlineimap.__license__))