[Travis] fix macos timeout message

Author: 3nids

.ci/travis/macos/script.sh

@@ -35,7 +35,7 @@ gtimeout ${TIMEOUT}s ctest -V -E "$(cat ${DIR}/blacklist.txt | gsed -r '/^(#.*?)
 
 rv=$?
 
-if [ $? -eq 124 ] ; then
+if [ $rv -eq 124 ] ; then
     echo '\033[0;33mBuild and test timeout. Please restart the build for useful results.\033[0m'
 fi