Blender Git Loki

Fix T87264: Button to remove physics modifier doesn't work

This is caused by rB9f323e9bf79f. When hover shortcuts are used,
we cannot use the modifier from the context (which will be the
active modifier), or they won't be hover shortcuts anymore!

There didn't use to be an editor-level "modifier" context variable,
which is why this worked before.

The fix is simple, just specify the modifier name for this particular
remove button.

Differential Revision: https://developer.blender.org/D10870