Catch RuntimeError when importing Qt4

In case PySide is already imported

PIL/ImageQt.py

@@ -31,7 +31,7 @@
         from PyQt4.QtGui import QImage, qRgba, QPixmap
         from PyQt4.QtCore import QBuffer, QIODevice
         qt_version = '4'
-    except ImportError:
+    except (ImportError, RuntimeError):
         try:
             from PySide.QtGui import QImage, qRgba, QPixmap
             from PySide.QtCore import QBuffer, QIODevice