TextEditor: CodeAssist: Initialize all pointer members to 0

Change-Id: I82ada400aeca5e4a4f5facf64f3f7f7d5d378b06
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/texteditor/codeassist/codeassistant.cpp

@@ -142,6 +142,7 @@ static const int AutomaticProposalTimerInterval = 400;
 CodeAssistantPrivate::CodeAssistantPrivate(CodeAssistant *assistant)
     : m_q(assistant)
     , m_textEditor(0)
+    , m_completionProvider(0)
     , m_requestRunner(0)
     , m_requestProvider(0)
     , m_proposalWidget(0)