GlslEditor: Fix crash
GlslEditor: Fix crash

Task-number: QTCREATORBUG-14116
Change-Id: I48549806b7108d31519dc573039496b727e7a0af
Reviewed-by: Nikolai Kosjar <9571db158ca61a0d070db010803474231fa0cbab@theqtcompany.com>

danimo/qt-creator,Distrotech/qtcreator,xianian/qt-creator,Distrotech/qtcreator,danimo/qt-creator,danimo/qt-creator,Distrotech/qtcreator,danimo/qt-creator,danimo/qt-creator,danimo/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,Distrotech/qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,Distrotech/qtcreator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,danimo/qt-creator