Options such as:
osd mount options xfs = -i size=2048 -n size=16k
were parsed as:
key: 'osd mount options xfs = -i size=2048 -n size'
value: '16k'
This is due to the greedy .* in the beginning. Making it
non-greedy fixes this.
Fixes#851
verify_blockdev_path didn't check the result of abs_path
causing commands like `pveceph createosd bad/path` to error
with a meaningless "Use of uninitialized value" message.