Fixup command names in some usage strings.

Most usage strings, such as for command xxx, start with "git-xxx".
This updates the rebels to conform to the general pattern.
(The git wrapper is an exception to this, of course ...)
Signed-off-by: NRamsay Allan Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

blame.c

@@ -20,7 +20,7 @@
 
 #define DEBUG 0
 
-static const char blame_usage[] = "[-c] [-l] [-t] [-S <revs-file>] [--] file [commit]\n"
+static const char blame_usage[] = "git-blame [-c] [-l] [-t] [-S <revs-file>] [--] file [commit]\n"
 	"  -c, --compatibility Use the same output mode as git-annotate (Default: off)\n"
 	"  -l, --long          Show long commit SHA1 (Default: off)\n"
 	"  -t, --time          Show raw timestamp (Default: off)\n"

builtin-diff.c

@@ -23,7 +23,7 @@ struct blobinfo {
 };
 
 static const char builtin_diff_usage[] =
-"diff <options> <rev>{0,2} -- <path>*";
+"git-diff <options> <rev>{0,2} -- <path>*";
 
 static int builtin_diff_files(struct rev_info *revs,
 			      int argc, const char **argv)

builtin-push.c

@@ -8,7 +8,7 @@
 
 #define MAX_URI (16)
 
-static const char push_usage[] = "git push [--all] [--tags] [-f | --force] <repository> [<refspec>...]";
+static const char push_usage[] = "git-push [--all] [--tags] [-f | --force] <repository> [<refspec>...]";
 
 static int all = 0, tags = 0, force = 0, thin = 1;
 static const char *execute = NULL;

mktag.c

@@ -123,7 +123,7 @@ int main(int argc, char **argv)
 	unsigned char result_sha1[20];
 
 	if (argc != 1)
-		usage("cat <signaturefile> | git-mktag");
+		usage("git-mktag < signaturefile");
 
 	setup_git_directory();
 

mktree.c

@@ -71,7 +71,7 @@ static void write_tree(unsigned char *sha1)
 	write_sha1_file(buffer, offset, tree_type, sha1);
 }
 
-static const char mktree_usage[] = "mktree [-z]";
+static const char mktree_usage[] = "git-mktree [-z]";
 
 int main(int ac, char **av)
 {