Add a unit test to verify that 'xenstore-ls' works in the 'quota' filesystem

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xenstored: the 'list directory' function is called 'ls' not 'list'

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #25 from djs55/irminsule

Fix regression when 'list'ing synthetic filesystems