qemu: domain: Add helper to access vm->privateData->agent

As in commit 88dc7e0c, the helper can be used in cases where the
function actually does not access anyting in the private data besides
the agent.

src/qemu/qemu_domain.c

@@ -1872,6 +1872,18 @@ qemuDomainObjEnterMonitorAsync(virQEMUDriverPtr driver,
 }
 
 
+/**
+ * qemuDomainGetAgent:
+ * @vm: domain object
+ *
+ * Returns the agent pointer of @vm;
+ */
+qemuAgentPtr
+qemuDomainGetAgent(virDomainObjPtr vm)
+{
+    return (((qemuDomainObjPrivatePtr)(vm->privateData))->agent);
+}
+
 
 /*
  * obj must be locked before calling

src/qemu/qemu_domain.h

@@ -298,6 +298,7 @@ int qemuDomainObjEnterMonitorAsync(virQEMUDriverPtr driver,
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 
 
+qemuAgentPtr qemuDomainGetAgent(virDomainObjPtr vm);
 void qemuDomainObjEnterAgent(virDomainObjPtr obj)
     ATTRIBUTE_NONNULL(1);
 void qemuDomainObjExitAgent(virDomainObjPtr obj)