incron state: rm unused import

************* Module salt.states.incron
salt/states/incron.py:44: [W0611(unused-import), ] Unused import os
salt/states/incron.py:47: [W0611(unused-import), ] Unused import salt
salt/states/incron.py:49: [W0611(unused-import), ] Unused import _needs_change
Merge pull request #9384 from cvrebert/patch-1

incron state: rm unused imports