Re-enable stacktracing when --debug is used

Commit 1f89beb609 introduced the behaviour
that a stacktrace is printed if an exception is encountered.

This helped make the client more supportable:

 $ glance --debug image-list
  .
  .
  .
  File "glanceclient/common/http.py", line 337, in get_http_client
    xxx
 NameError: global name 'xxx' is not defined
 global name 'xxx' is not defined

The behaviour was lost at some point. This patch re-enables it.

Change-Id: I25fc8624797909d606590747f54b9cf649ade079
Closes-bug: 1563830

glanceclient/shell.py

@@ -489,18 +489,12 @@ class OpenStackImagesShell(object):
             try:
                 return self.get_subcommand_parser(api_version)
             except ImportError as e:
-                if options.debug:
-                    traceback.print_exc()
                 if not str(e):
                     # Add a generic import error message if the raised
                     # ImportError has none.
                     raise ImportError('Unable to import module. Re-run '
                                       'with --debug for more info.')
                 raise
-            except Exception:
-                if options.debug:
-                    traceback.print_exc()
-                raise
 
         # Parse args once to find version
 
@@ -595,12 +589,6 @@ class OpenStackImagesShell(object):
             args.func(client, args)
         except exc.Unauthorized:
             raise exc.CommandError("Invalid OpenStack Identity credentials.")
-        except Exception:
-            # NOTE(kragniz) Print any exceptions raised to stderr if the
-            # --debug flag is set
-            if args.debug:
-                traceback.print_exc()
-            raise
         finally:
             if profile:
                 trace_id = osprofiler_profiler.get().get_base_id()
@@ -671,4 +659,6 @@ def main():
     except KeyboardInterrupt:
         utils.exit('... terminating glance client', exit_code=130)
     except Exception as e:
+        if utils.debug_enabled(argv) is True:
+            traceback.print_exc()
         utils.exit(encodeutils.exception_to_unicode(e))