(maint) Fix fact-node globbing tests

The regular expression I provided for the glob replace wasn't sufficient for
PostgreSQL to work. This patch amends it to be so.

I've also put in a test for keys with blank strings, to make sure this change
doesn't affect that case as well.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #1032 from kbarber/maint/master/fix-globbing-tests

(maint) Fix fact-node globbing tests
(PDB-763) Provide trgm index handling for fact_paths

This patch adds a detection routine outside of the normal migration that will
nag the user if they don't have pg_trgm installed (or don't have a compatible
system for trgm and regexp performance, ie. pg 9.3 or above).

If trgm is working, it will manage installing the correct index on the
fact_paths table for regular expression query optimization.

Without a trgm index, globbing and regular expression queries will not use
an index and thus those queries become full table scans.

Signed-off-by: Ken Barber <ken@bob.sh>