Medium: fix exportfs monitor action for special characters and common suffixes

Trying to match a multiline blob against an unquoted single line literal
string, interpreted as unanchored regular expression, does not work.

The directory name (or more likely, client spec) may contain regex
"special" characters, such as a '*' wildcard, which caused the previous
monitor action implementation to fail.

Also, if /foo/bar was exported, but /bar was not,
still the monitoring for /bar would return "running"
(if exported to a similar enough client spec).

Fixed by unwrapping the output of exportfs,
then doing a line-wise literal match.