coverity#1430100 Uninitialized pointer field

Change-Id: I6d544b97c2b22a16d6a12b898cbe25580c433b61
Reviewed-on: https://gerrit.libreoffice.org/51570Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/attr/calbck.cxx

@@ -28,8 +28,8 @@
 sw::LegacyModifyHint::~LegacyModifyHint() {}
 sw::ModifyChangedHint::~ModifyChangedHint() {}
 
-
 SwClient::SwClient(SwClient&& o)
+    : m_pRegisteredIn(nullptr)
 {
     if(o.m_pRegisteredIn)
     {
@@ -38,7 +38,6 @@ SwClient::SwClient(SwClient&& o)
     }
 }
 
-
 SwClient::~SwClient()
 {
     if(GetRegisteredIn())