Further clean-up: usage() vs die()

This hopefully finishes the clean-up Ramsay started with recent
commit 15e593e4 and commit
8cdf3364.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

builtin-check-ref-format.c

@@ -9,6 +9,6 @@
 int cmd_check_ref_format(int argc, const char **argv, const char *prefix)
 {
 	if (argc != 2)
-		usage("git check-ref-format refname");
+		usage("git-check-ref-format refname");
 	return !!check_ref_format(argv[1]);
 }

builtin-mv.c

@@ -99,7 +99,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			ignore_errors = 1;
 			continue;
 		}
-		die(builtin_mv_usage);
+		usage(builtin_mv_usage);
 	}
 	count = argc - i - 1;
 	if (count < 1)

builtin-prune.c

@@ -10,7 +10,7 @@
 #include "builtin.h"
 #include "cache-tree.h"
 
-static const char prune_usage[] = "git prune [-n]";
+static const char prune_usage[] = "git-prune [-n]";
 static int show_only = 0;
 static struct rev_info revs;
 

builtin-rm.c

@@ -115,7 +115,7 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 		printf("rm '%s'\n", path);
 
 		if (remove_file_from_cache(path))
-			die("git rm: unable to remove %s", path);
+			die("git-rm: unable to remove %s", path);
 		cache_tree_invalidate_path(active_cache_tree, path);
 	}
 
@@ -139,7 +139,7 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 				continue;
 			}
 			if (!removed)
-				die("git rm: %s: %s", path, strerror(errno));
+				die("git-rm: %s: %s", path, strerror(errno));
 		}
 	}