[PATCH] git: Mention the '-p' option in the usage help string if git-diff-tree.

Mention the '-p' option in the usage help string of git-diff-tree.
Signed-Off-by: NThomas Glanzmann <sithglan@stud.uni-erlangen.de>
Signed-Off-by: NLinus Torvalds <torvalds@osdl.org>

diff-tree.c

@@ -250,7 +250,7 @@ static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, co
 	return retval;
 }
 
-static char *diff_tree_usage = "diff-tree [-r] [-z] <tree sha1> <tree sha1>";
+static char *diff_tree_usage = "diff-tree [-p] [-r] [-z] <tree sha1> <tree sha1>";
 
 int main(int argc, char **argv)
 {