rigidbody: Fix [#34106] Deleting an object with Bullet Constraint crashes Blender

Constraints are deleted before rigid bodies so need to check if constraint
exists in case both the constraint and ridid body are on the same object.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54307 954f8c5b-7b00-dc11-b283-0030488c597c
rigidbody: Don't allow collision shape to be animated

While it's fun to be able to change collison shape while the simulation is
running it can cause crashes in some cases.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54308 954f8c5b-7b00-dc11-b283-0030488c597c
rigidbody: Fix [#34108] Rigid body with no polygons crashes blender

Fall back to using box shape in case creating shape from mesh fails.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54309 954f8c5b-7b00-dc11-b283-0030488c597c
rigidbody: Avoid always making passive objects kinematic

It's only needed when they're being transformed.
Also deactivate passive objects after transformation so they don't keep
acitvating deactivated objects.

Fixes issues with using "start deactivated".

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54310 954f8c5b-7b00-dc11-b283-0030488c597c