fix error msg: msgb_put(): say "msgb_put", not "msgb_push"

Change-Id: I72f31ebad693f98eb088a99b83aeb10cf9acc29e
diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h
index b057caa..6f617e2 100644
--- a/include/osmocom/core/msgb.h
+++ b/include/osmocom/core/msgb.h
@@ -185,7 +185,7 @@
 {
 	unsigned char *tmp = msgb->tail;
 	if (msgb_tailroom(msgb) < (int) len)
-		MSGB_ABORT(msgb, "Not enough tailroom msgb_push (%u < %u)\n",
+		MSGB_ABORT(msgb, "Not enough tailroom msgb_put (%u < %u)\n",
 			   msgb_tailroom(msgb), len);
 	msgb->tail += len;
 	msgb->len += len;