Fix T49349: Baking action doesnt bake multiple objects.

Tooltip was wrong here, it can only bake a single (active) object, 'only selected' option
is for pose bones only...

release/scripts/modules/bpy_extras/anim_utils.py

@@ -49,7 +49,7 @@ def bake_action(frame_start,
     :type frame_end: int
     :arg frame_step: Frame step.
     :type frame_step: int
-    :arg only_selected: Only bake selected data.
+    :arg only_selected: Only bake selected bones.
     :type only_selected: bool
     :arg do_pose: Bake pose channels.
     :type do_pose: bool

release/scripts/startup/bl_operators/anim.py

@@ -222,7 +222,7 @@ class BakeAction(Operator):
             )
     only_selected = BoolProperty(
             name="Only Selected",
-            description="Only key selected object/bones",
+            description="Only key selected bones (Pose baking only)",
             default=True,
             )
     visual_keying = BoolProperty(