Replace virDomainSnapshotFree with virObjectUnref

Since virDomainSnapshotFree will call virObjectUnref anyway, let's just use
that directly so as to avoid the possibility that we inadvertently clear out
a pending error message when using the public API.

cfg.mk

@@ -992,7 +992,7 @@ sc_prohibit_system_error_with_vir_err:
 # functions. There's a corresponding exclude to allow usage within tests,
 # docs, examples, tools, src/libvirt-*.c, and include/libvirt/libvirt-*.h
 sc_prohibit_virXXXFree:
-	@prohibit='\bvir(Domain|Network|NodeDevice|StorageVol|StoragePool|Stream|Secret|NWFilter|Interface)Free\b'	\
+	@prohibit='\bvir(Domain|Network|NodeDevice|StorageVol|StoragePool|Stream|Secret|NWFilter|Interface|DomainSnapshot)Free\b'	\
 	exclude='sc_prohibit_virXXXFree' \
 	halt='avoid using 'virXXXFree', use 'virObjectUnref' instead' \
 	  $(_sc_search_regexp)
@@ -1186,4 +1186,4 @@ exclude_file_name_regexp--sc_prohibit_devname = \
   ^(tools/virsh.pod|cfg.mk|docs/.*)$$
 
 exclude_file_name_regexp--sc_prohibit_virXXXFree = \
-  ^(docs/|tests/|examples/|tools/|cfg.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface).c$$)
+  ^(docs/|tests/|examples/|tools/|cfg.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).c$$)

daemon/remote.c

@@ -4535,7 +4535,7 @@ remoteDispatchDomainListAllSnapshots(virNetServerPtr server ATTRIBUTE_UNUSED,
     virObjectUnref(dom);
     if (snaps && nsnaps > 0) {
         for (i = 0; i < nsnaps; i++)
-            virDomainSnapshotFree(snaps[i]);
+            virObjectUnref(snaps[i]);
         VIR_FREE(snaps);
     }
     return rv;
@@ -4600,12 +4600,11 @@ remoteDispatchDomainSnapshotListAllChildren(virNetServerPtr server ATTRIBUTE_UNU
  cleanup:
     if (rv < 0)
         virNetMessageSaveError(rerr);
-    if (snapshot)
-        virDomainSnapshotFree(snapshot);
+    virObjectUnref(snapshot);
     virObjectUnref(dom);
     if (snaps && nsnaps > 0) {
         for (i = 0; i < nsnaps; i++)
-            virDomainSnapshotFree(snaps[i]);
+            virObjectUnref(snaps[i]);
         VIR_FREE(snaps);
     }
     return rv;

src/qemu/qemu_driver.c

@@ -14079,7 +14079,7 @@ qemuDomainSnapshotCreateXML(virDomainPtr domain,
                                             cfg->snapshotDir) < 0) {
             /* if writing of metadata fails, error out rather than trying
              * to silently carry on without completing the snapshot */
-            virDomainSnapshotFree(snapshot);
+            virObjectUnref(snapshot);
             snapshot = NULL;
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("unable to save metadata for snapshot %s"),

src/remote/remote_driver.c

@@ -6766,8 +6766,7 @@ remoteDomainListAllSnapshots(virDomainPtr dom,
  cleanup:
     if (snaps) {
         for (i = 0; i < ret.snapshots.snapshots_len; i++)
-            if (snaps[i])
-                virDomainSnapshotFree(snaps[i]);
+            virObjectUnref(snaps[i]);
         VIR_FREE(snaps);
     }
 
@@ -6833,8 +6832,7 @@ remoteDomainSnapshotListAllChildren(virDomainSnapshotPtr parent,
  cleanup:
     if (snaps) {
         for (i = 0; i < ret.snapshots.snapshots_len; i++)
-            if (snaps[i])
-                virDomainSnapshotFree(snaps[i]);
+            virObjectUnref(snaps[i]);
         VIR_FREE(snaps);
     }