Bug#1020339: Gimp crash when use Text tool

[Bernhard Übelacker]

> /lib/x86_64-linux-gnu/libc.so.6(+0x3daf0)[0x7f650123daf0]
> /lib/x86_64-linux-gnu/libgobject-2.0.so.0(+0x25103)[0x7f650178c103]
> /lib/x86_64-linux-gnu/libgobject-2.0.so.0(+0x1b6d8)[0x7f65017826d8]
> /lib/x86_64-linux-gnu/libgobject-2.0.so.0(+0x1bf5a)[0x7f6501782f5a]
> /lib/x86_64-linux-gnu/libgobject-2.0.so.0(g_object_new_with_properties+0x194)[0x7f65017843f4]
> gimp(gimp_image_undo_push+0x1a7)[0x55fe29a3e787]
> gimp(gimp_image_undo_push_text_layer+0x104)[0x55fe29a41344]
> gimp(gimp_text_tool_apply+0x103)[0x55fe29770e93]


Frames below signal handler are looking similar to #1018105.