Blender Git Loki

Fix: Only change transform mode from translation to rotation/scale when no valid bones were found in an armature

This commit fixes a problem the Spring team were having in the shot files 01_030/050 with
the camera rig, where when you tried grabbing/translating the bones of the camera rig,
they would only keep rotating/scaling instead.

The reason for this is that with the multi-object editing support added into the transform
system, this code would now get run for all the other objects that were being included
in Pose Mode, even if no bones from those armatures were selected. Since no valid translatable
bones were found in those other armatures, the transform mode would get reset upon
encountering one of those other bones.