Set correct 'mountable' flag.

git-svn-id: svn://svn.code.sf.net/p/openmediavault/code@1503 3c3d7b80-5828-415e-9f61-280b98178fff
Improve omv_trim, omv_ltrim and omv_rtrim shell functions.

git-svn-id: svn://svn.code.sf.net/p/openmediavault/code@1504 3c3d7b80-5828-415e-9f61-280b98178fff