mon query ls: Simplify list filtering
Previously, to find all hosts which ContactX was *not* added to,
you had to negate a "greater or equal" query, like this:
mon query ls hosts -c name contacts -ge ContactX -n
or,
mon query ls hosts -c name 'contacts>=ContactX' -n
Now, you can *also* do like this:
mon query ls hosts -c name contacts -nct ContactX
or,
mon query ls hosts -c name 'contacts!>=ContactX'
Change-Id: I4addead0c8f7882d81fea35ebe3cb71be0f0287b
Signed-off-by: Philip Eklöf <peklof@op5.com>