Fix uninitialized variable warning

health/mcap.c: In function ‘proc_req_pending’:
health/mcap.c:1119:25: error: ‘abrt’ may be used uninitialized in this function
make[1]: *** [health/mcap.o] Error 1
diff --git a/health/mcap.c b/health/mcap.c
index 81fd8df..48866d4 100644
--- a/health/mcap.c
+++ b/health/mcap.c
@@ -1126,6 +1126,7 @@
 	req = cmd;
 	mdl_id = ntohs(req->mdl);
 	mcl->state = MCL_CONNECTED;
+	abrt = NULL;
 	for (l = mcl->mdls; l; l = l->next) {
 		mdl = l->data;
 		if (mdl_id == mdl->mdlid && mdl->state == MDL_WAITING) {