Fixed #2995 execution of 'after_cd' hooks

Problem description:

'rmv_path/scripts/hook' ( http://git.io/PwckwQ ) contains:
  hooks=( "$rvm_hooks_path")
  [[ "$PWD/.rvm/hooks" == "$rvm_hooks_path" ]] ||
    hooks+=( "$PWD/.rvm/hooks" )

  _hooks_list=($(
    __rvm_find -L "${hooks[@]}" -iname "$rvm_hook*" -type f 2>/dev/null
  ))

but when env is not loaded $rvm_hooks_path is undefined. This leads
to '${hooks[@]}' contains a space and 'find' will fail with
'find: ftsopen: No such file or directory' and tnx to '2>/dev/null'
error will be invisible.
Updated 'after_use' hook invocation.

Just to make hooks invocation identical across the project
Merge pull request #3018 from mshytikov/fix-hooks

Fix hooks