buildman: Add a flag to control the traceback

At present the full horror of the Python traceback is shown by default. It
is normally only useful for debugging. Turn it off by default and add a
--debug flag to enable it.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/buildman/cmdline.py

@@ -32,6 +32,8 @@ def ParseArgs():
           help='Show detailed size delta for each board in the -S summary')
     parser.add_option('-D', '--config-only', action='store_true', default=False,
           help="Don't build, just configure each commit")
+    parser.add_option('--debug', action='store_true',
+        help='Enabling debugging (provides a full traceback on error)')
     parser.add_option('-e', '--show_errors', action='store_true',
           default=False, help='Show errors and warnings')
     parser.add_option('-E', '--warnings-as-errors', action='store_true',

tools/buildman/main.py

@@ -54,6 +54,9 @@ def RunTests(skip_net_tests):
 
 options, args = cmdline.ParseArgs()
 
+if not options.debug:
+    sys.tracebacklimit = 0
+
 # Run our meagre tests
 if options.test:
     RunTests(options.skip_net_tests)