ch_process: Check whether domain is already running before starting it

There are two places where a domain can be started in CH driver:
chDomainCreateXML() and chDomainCreateWithFlags(). Both acquire a
job (good), but neither of them checks whether the domain isn't
already running. This is wrong. Fortunately, both function call
the very same virCHProcessStart() rendering it the best place for
such check.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Tim Wiederhake <twiederh@redhat.com>

src/ch/ch_process.c

@@ -470,6 +470,12 @@ virCHProcessStart(virCHDriver *driver,
     g_autofree int *nicindexes = NULL;
     size_t nnicindexes = 0;
 
+    if (virDomainObjIsActive(vm)) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("VM is already active"));
+        return -1;
+    }
+
     if (!priv->monitor) {
         /* And we can get the first monitor connection now too */
         if (!(priv->monitor = virCHProcessConnectMonitor(driver, vm))) {