locking: Remove unnecessary setting of lockspace

In virLockSpaceProtocolDispatchNew() the returned value of lockspace from
virLockDaemonFindLockSpace() is overwritten by the virLockSpaceNew() return.
Coverity complains that it's unused.

In virLockSpaceProtocolDispatchCreateLockSpace() lockspace is also overwritten
in a similar manner resulting in the same Coverity message.

src/locking/lock_daemon_dispatch.c

@@ -227,7 +227,7 @@ virLockSpaceProtocolDispatchNew(virNetServerPtr server ATTRIBUTE_UNUSED,
         goto cleanup;
     }
 
-    if ((lockspace = virLockDaemonFindLockSpace(lockDaemon, args->path))) {
+    if (virLockDaemonFindLockSpace(lockDaemon, args->path) != NULL) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("Lockspace for path %s already exists"),
                        args->path);
@@ -406,7 +406,7 @@ virLockSpaceProtocolDispatchCreateLockSpace(virNetServerPtr server ATTRIBUTE_UNU
         goto cleanup;
     }
 
-    if ((lockspace = virLockDaemonFindLockSpace(lockDaemon, args->path))) {
+    if (virLockDaemonFindLockSpace(lockDaemon, args->path) != NULL) {
         virReportError(VIR_ERR_OPERATION_INVALID,
                        _("Lockspace for path %s already exists"),
                        args->path);