Handle traceback when OptionValueError raised during init.

Turn it into a UsageError for now. This causes it to report the
failing config option and print the help text for init. Printing the
help text may not be needed, but it works for now.

Author: rouilj

roundup/admin.py

@@ -36,7 +36,7 @@
 from roundup import __version__ as roundup_version
 import roundup.instance
 from roundup.configuration import (CoreConfig, NoConfigError, OptionUnsetError,
-                                   ParsingOptionError, UserConfig)
+                                   OptionValueError, ParsingOptionError, UserConfig)
 from roundup.i18n import _, get_translation
 from roundup.exceptions import UsageError
 from roundup.anypy.my_input import my_input
@@ -1107,6 +1107,8 @@ def do_initialise(self, tracker_home, args):
             tracker = roundup.instance.open(tracker_home)
         except roundup.instance.TrackerError:
             raise UsageError(_('Instance has not been installed') % locals())
+        except OptionValueError as e:
+            raise UsageError(e)
 
         # is there already a database?
         if tracker.exists():