Plane: Initialize a string array

ArduPlane/AP_Arming.cpp

@@ -158,7 +158,7 @@ bool AP_Arming_Plane::quadplane_checks(bool display_failure)
     }
 
     // ensure controllers are OK with us arming:
-    char failure_msg[50];
+    char failure_msg[50] = {};
     if (!plane.quadplane.pos_control->pre_arm_checks("PSC", failure_msg, ARRAY_SIZE(failure_msg))) {
         check_failed(ARMING_CHECK_PARAMETERS, display_failure, "Bad parameter: %s", failure_msg);
         ret = false;