toollabs/sql: Add handling for connecting to "meta_p"

The special "meta" table doesn't have a *.labsdb hostname and as
such isn't found by the /etc/hosts. This one needs local handling
in order to work like "sql meta" or "sql meta_p".

Change-Id: If7f0f94b11db6dd7eea03f2ef845fe4883d88db7