Avoid double free in qemuMonitorCommonTestInit on OOM

The qemuMonitorCommonTestInit method did not allocate the
test object, so it should not free it upon failure. Doing
so causes a double free with the caller.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

tests/qemumonitortestutils.c

@@ -849,7 +849,6 @@ qemuMonitorCommonTestInit(qemuMonitorTestPtr test)
     return 0;
 
 error:
-    qemuMonitorTestFree(test);
     return -1;
 }