Disable shader based rounded corners for card applications

When launching an application with support for shader based rounded corners enabled it
will segfault:

Program received signal SIGSEGV, Segmentation fault.
0x41c53d54 in QGLCustomShaderStage::setOnPainter(QPainter*) () from /usr/lib/libQtOpenGL.so.4
(gdb) bt
0  0x41c53d54 in QGLCustomShaderStage::setOnPainter(QPainter*) () from /usr/lib/libQtOpenGL.so.4
1  0x000d5c80 in CardLoading::paint (this=0x45434728, painter=0xbe8b2ea4, maximized=<optimized out>) at Src/lunaui/cards/CardLoading.cpp:264
2  0x000d0768 in CardWindow::paint (this=0x4539ec10, painter=0xbe8b2ea4, option=<optimized out>, widget=<optimized out>) at Src/lunaui/cards/CardWindow.cpp:1509
3  0x41fcd3c0 in ?? () from /usr/lib/libQtGui.so.4
4  0x41fcd3c0 in ?? () from /usr/lib/libQtGui.so.4

Open-webOS-DCO-1.0-Signed-off-by: Simon Busch <morphis@gravedo.de>