mv: prevent mismatched data when ignoring errors.

We shrink the source and destination arrays, but not the modes or
submodule_gitfile arrays, resulting in potentially mismatched data.  Shrink
all the arrays at the same time to prevent this.  Add tests to ensure the
problem does not recur.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/mv.c

@@ -231,6 +231,11 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 					memmove(destination + i,
 						destination + i + 1,
 						(argc - i) * sizeof(char *));
+					memmove(modes + i, modes + i + 1,
+						(argc - i) * sizeof(enum update_mode));
+					memmove(submodule_gitfile + i,
+						submodule_gitfile + i + 1,
+						(argc - i) * sizeof(char *));
 					i--;
 				}
 			} else