If a wrong command name is used (e.g. typo), cmdhelp is triggered.
However, if user specifies any additional arguments (other than -h),
then user is presented with not so useful message.

This CL calls cmdhelp with no arguments.

Fixed: 1352093
Change-Id: I30c0b5f580f18b4fa2cb59d3195b67bb083f3442
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3828794Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>