Update qemu-sbruno and qemu-user-static to 2.9.50

• Fix handling of ino64 changes in head (Michal Meloun)
• Don't return 0 if pending signal is detected before call to real select(). This causes cmake timeout failures - a select() with NULL as timeout argument returns (erroneously) 0. (Michal Meloun)
• Allow users to compile bsd-user dynamically (Michal Meloun)