fix rpc-tests.sh

`${testScripts[@]}` now does split up `testscript --agument` in two elements pushed to the array (`testscript` and `--agument`).

qa/pull-tester/rpc-tests.sh

@@ -60,7 +60,7 @@ testScriptsExt=(
 );
 
 if [ "x$ENABLE_ZMQ" = "x1" ]; then
-  testScripts=( ${testScripts[@]} 'zmq_test.py' )
+  testScripts+=('zmq_test.py')
 fi
 
 extArg="-extended"