Refresh modules for certain file.symlink states

This commit refreshes modules when there are changes in a file.symlink
state with 'bin' in the name. Making this distinction keeps refreshes
from being done for all symlinks, reducing the amount of overhead this
change would introduce. A symlink with 'bin' in the name is likely to
change the available commands on the minion, and thus might make
available certain states/modules which rely on the existence of a given
command in the user's PATH. Without a refresh, these states/module
function calls would fail despite the needed shell command technically
being available.