*: use "can't" instead of "cannot"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/id.c b/coreutils/id.c
index 6022c9f..ec9227d0 100644
--- a/coreutils/id.c
+++ b/coreutils/id.c
@@ -175,7 +175,7 @@
 			}
 		} else if (n < 0) { /* error in get_groups() */
 			if (!ENABLE_DESKTOP)
-				bb_error_msg_and_die("cannot get groups");
+				bb_error_msg_and_die("can't get groups");
 			else
 				return EXIT_FAILURE;
 		}