Simplify bhyveDriverGetCapabilities()

The driver passed as the only argument to the function should never be
NULL so there's no need to check it. After removing it, the whole
function collapses to a single line doing ref over driver
capabilities.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/bhyve/bhyve_driver.c

@@ -2,6 +2,7 @@
  * bhyve_driver.c: core driver methods for managing bhyve guests
  *
  * Copyright (C) 2014 Roman Bogorodskiy
+ * Copyright (C) 2014 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -123,16 +124,10 @@ bhyveAutostartDomains(bhyveConnPtr driver)
  * Returns: a reference to a virCapsPtr instance or NULL
  */
 static virCapsPtr
-bhyveDriverGetCapabilities(bhyveConnPtr driver)
+bhyveDriverGetCapabilities(bhyveConnPtr driver ATTRIBUTE_NONNULL)
 {
-    virCapsPtr ret = NULL;
 
-    if (driver == NULL)
-        return NULL;
-
-    ret = virObjectRef(driver->caps);
-
-    return ret;
+    return virObjectRef(driver->caps);
 }
 
 static char *