Fix thinko in the logic to refuse unmerged path fed to git-apply-patch-script.

An unmerged path is given as the sole parameter to the script, so it
should check against $# being 1, not 2.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-apply-patch-script

@@ -8,7 +8,7 @@
 #
 
 case "$#" in
-2)
+1)
     echo >&2 "cannot handle unmerged diff on path $1."
     exit 1 ;;
 esac