Do not use realpath() on fileio paths
Do not use realpath() on fileio paths

RBD creates block device nodes named /dev/rbd0 -> rbdX, but these may refer
to different volumes after reboot. Users should use consistent names like
/dev/rbd/foo/bar, these are symlinks to rbdX.

rtslib should not use realpath() to get the rbdX name, but should just use
what was given, which may be a symlink, but it will point to the right
rbdX.

Resolves #57

Signed-off-by: Andy Grover <b7d524d2f5cc5aebadb6b92b08d3ab26911cde33@redhat.com>

cvubrugier/rtslib-fb,agrover/rtslib-fb