- Make function of finding an available drive name a macro. - Move check of /dev/ prefix and copy into a function to save code duplication.   This also fixes a bug where the /dev/ prefix could not be used when creating   volumes on the command line.
- Make function of finding an available drive name a macro.
- Move check of /dev/ prefix and copy into a function to save code duplication.
  This also fixes a bug where the /dev/ prefix could not be used when creating
  volumes on the command line.

Tested by:	Niclas Zeising <niclas.zeising - at - gmail.com>

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