network: Fix virNetworkObjBridgeInUse return type

Rather than an int, it returns a bool - so let's define it that way
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/conf/virnetworkobj.c

@@ -1172,7 +1172,7 @@ virNetworkObjBridgeInUseHelper(const void *payload,
 }
 
 
-int
+bool
 virNetworkObjBridgeInUse(virNetworkObjListPtr nets,
                          const char *bridge,
                          const char *skipname)

src/conf/virnetworkobj.h

@@ -174,7 +174,7 @@ virNetworkObjDeleteConfig(const char *configDir,
                           const char *autostartDir,
                           virNetworkObjPtr net);
 
-int
+bool
 virNetworkObjBridgeInUse(virNetworkObjListPtr nets,
                          const char *bridge,
                          const char *skipname);