checkpatch: remove obsolete period from "ambiguous SHA1" query

checkpatch: remove obsolete period from "ambiguous SHA1" query

Git dropped the period from its "ambiguous SHA1" error message in commit
0c99171ad2 ("get_short_sha1: mark ambiguity error for translation"), circa
2016.  Drop the period from checkpatch's associated query so as to match
both the old and new error messages.

Link: http://lkml.kernel.org/r/20190830163103.15914-1-sean.j.christopherson@intel.com
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>