qemu: Remove duplicated qemuAgentCheckError

Commit 5b3492fa moved qemuAgentCheckError calls into
qemuAgentCommand for various reasons; however, subsequent
commit 0977b8aa adding a new command made call again
So let's just remove the duplicitous call from
qemuAgentGetInterfaces.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>
ACKed-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_agent.c

@@ -2035,10 +2035,9 @@ qemuAgentGetInterfaces(qemuAgentPtr mon,
     if (!(cmd = qemuAgentMakeCommand("guest-network-get-interfaces", NULL)))
         goto cleanup;
 
-    if (qemuAgentCommand(mon, cmd, &reply, false, VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK) < 0 ||
-        qemuAgentCheckError(cmd, reply) < 0) {
+    if (qemuAgentCommand(mon, cmd, &reply, false,
+                         VIR_DOMAIN_QEMU_AGENT_COMMAND_BLOCK) < 0)
         goto cleanup;
-    }
 
     if (!(ret_array = virJSONValueObjectGet(reply, "return"))) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",