Framework: Use -c instead of -C to execute payload

-C will execute the file when it doesn't have the executable bit set, however, it will also set the noclobber option and prevent overwriting files. To use -c instead, we must set the executable bit for the user in case they haven't done it themselves.

usr/bin/shark_framework

@@ -128,7 +128,8 @@ function execute_payload() {
             ;;
         "payload" | "payload.sh" | "payload.txt")
             sed -i 's/\r//g' $payload
-            echo "bash -C '$payload'" | at now
+            chmod +x $payload
+            echo "bash -c '$payload'" | at now
             ;;
         *)
             /usr/bin/LED FAIL