rt-migrate-test: exit early if nr_runs is non-positive

Program will crash if nr_runs is 0 due to dividing by it in
print_results(). Let's exit early instead.

Fixes: http://bugs.debian.org/716237
Signed-off-by: Boris Egorov <egorov@linux.com>
Signed-off-by: Clark Williams <williams@redhat.com>
diff --git a/src/rt-migrate-test/rt-migrate-test.c b/src/rt-migrate-test/rt-migrate-test.c
index e3c7a09..711d8a4 100644
--- a/src/rt-migrate-test/rt-migrate-test.c
+++ b/src/rt-migrate-test/rt-migrate-test.c
@@ -226,7 +226,10 @@
 			break;
 		}
 	}
-
+	if (nr_runs <= 0) {
+		fprintf(stderr, "Warning, --loops argument is non-positive.  Exiting.\n");
+		exit(-1);
+	}
 }
 
 static unsigned long long get_time(void)