DiffEditor: fix crash on diff action
DiffEditor: fix crash on diff action

Fix crash in GitClient::findExistingOrOpenNewDiffEditor as new DiffEditor
is not created

Change-Id: I7f0cd18ff3acffe1d83a5fad4d6f0df8c4d133f3
Reviewed-by: Eike Ziller <c142da16c73a95a82d35191bcc55b22835617128@digia.com>

darksylinc/qt-creator,richardmg/qtcreator,xianian/qt-creator,colede/qtcreator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,malikcjm/qtcreator,omniacreator/qtcreator,kuba1/qtcreator,darksylinc/qt-creator,Distrotech/qtcreator,amyvmiwei/qt-creator,darksylinc/qt-creator,maui-packages/qt-creator,kuba1/qtcreator,farseerri/git_code,xianian/qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,xianian/qt-creator,richardmg/qtcreator,colede/qtcreator,xianian/qt-creator,kuba1/qtcreator,maui-packages/qt-creator,danimo/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,darksylinc/qt-creator,martyone/sailfish-qtcreator,colede/qtcreator,xianian/qt-creator,kuba1/qtcreator,omniacreator/qtcreator,kuba1/qtcreator,xianian/qt-creator,Distrotech/qtcreator,omniacreator/qtcreator,amyvmiwei/qt-creator,Distrotech/qtcreator,xianian/qt-creator,omniacreator/qtcreator,danimo/qt-creator,colede/qtcreator,omniacreator/qtcreator,danimo/qt-creator,danimo/qt-creator,danimo/qt-creator,Distrotech/qtcreator,Distrotech/qtcreator,maui-packages/qt-creator,colede/qtcreator,farseerri/git_code,darksylinc/qt-creator,colede/qtcreator,martyone/sailfish-qtcreator,darksylinc/qt-creator,AltarBeastiful/qt-creator,darksylinc/qt-creator,kuba1/qtcreator,danimo/qt-creator,AltarBeastiful/qt-creator,danimo/qt-creator,richardmg/qtcreator,kuba1/qtcreator,maui-packages/qt-creator,danimo/qt-creator,darksylinc/qt-creator,Distrotech/qtcreator,richardmg/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,malikcjm/qtcreator,omniacreator/qtcreator,amyvmiwei/qt-creator,malikcjm/qtcreator,farseerri/git_code,AltarBeastiful/qt-creator,richardmg/qtcreator,farseerri/git_code,martyone/sailfish-qtcreator,farseerri/git_code,amyvmiwei/qt-creator,amyvmiwei/qt-creator,maui-packages/qt-creator,AltarBeastiful/qt-creator,maui-packages/qt-creator,farseerri/git_code,martyone/sailfish-qtcreator,richardmg/qtcreator,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,maui-packages/qt-creator,malikcjm/qtcreator,kuba1/qtcreator,farseerri/git_code,richardmg/qtcreator,danimo/qt-creator,amyvmiwei/qt-creator,xianian/qt-creator,omniacreator/qtcreator,colede/qtcreator,AltarBeastiful/qt-creator,malikcjm/qtcreator