SMPP: use proper type for boolean variables

Related: OS#5568
Change-Id: I033a2c863213a44f99827ef997f541a7a77f5d8a
diff --git a/src/libsmpputil/smpp_vty.c b/src/libsmpputil/smpp_vty.c
index fe5c22a..c6e6421 100644
--- a/src/libsmpputil/smpp_vty.c
+++ b/src/libsmpputil/smpp_vty.c
@@ -80,8 +80,8 @@
 			  const char *bind_addr, uint16_t port)
 {
 	struct smsc *smsc = smsc_from_vty(vty);
-	int is_running = smsc->listen_ofd.fd > 0;
-	int same_bind_addr;
+	bool is_running = smsc->listen_ofd.fd > 0;
+	bool same_bind_addr;
 	int rc;
 
 	/* If it is not up yet, don't rebind, just set values. */