git-gui: Fix parsing of <rev> <path-which-not-present-in-worktree>

Commit e3d06ca9 (git-gui: Detect full path when parsing arguments) broke git gui blame rev path-not-present-in-worktree in particular this does not work anymore: # in linux.git $ git gui blame 2bb8c26242c2393b097a993ffe9b003ec9b85395 drivers/net/sky2.c This patch restores the original functionality in this case. Acked-by: Andrew Wong <andrew.kw.w@gmail.com> Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>