Don't package the git-gui credits file anymore

Since git-gui 0.6.4 the credits file is no longer produced.
This file was removed from git-gui due to build issues that
a lot of users and Git developers have reported running into.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Makefile

@@ -901,8 +901,7 @@ dist: git.spec git-archive
 	$(TAR) rf $(GIT_TARNAME).tar \
 		$(GIT_TARNAME)/git.spec \
 		$(GIT_TARNAME)/version \
-		$(GIT_TARNAME)/git-gui/version \
-		$(GIT_TARNAME)/git-gui/credits
+		$(GIT_TARNAME)/git-gui/version
 	@rm -rf $(GIT_TARNAME)
 	gzip -f -9 $(GIT_TARNAME).tar