(PDB-904) Switch fact_values.value_string trgm index to be GIN not GIST
(PDB-904) Switch fact_values.value_string trgm index to be GIN not GIST

There were reports of crashing due to a bug in pg_trgm indexing when a large
fact value was loaded into PuppetDB.

This patch removes the old index via migration, and will then replace it with
the index handling mechanism.

Signed-off-by: Ken Barber <470bc578162732ac7f9d387d34c4af4ca6e1b6f7@bob.sh>

senior/puppetdb,shrug/puppetdb,rbrw/puppetdb,waynr/puppetdb,kbarber/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,wkalt/puppetdb,johnduarte/puppetdb,rbrw/puppetdb,grimradical/puppetdb,mullr/puppetdb,mullr/puppetdb,kbarber/puppetdb,kbrezina/puppetdb,senior/puppetdb,kbrezina/puppetdb,kbrezina/puppetdb,shrug/puppetdb,waynr/puppetdb,shrug/puppetdb,grimradical/puppetdb,johnduarte/puppetdb,senior/puppetdb,ajroetker/puppetdb,kbarber/puppetdb,grimradical/puppetdb,senior/puppetdb,rbrw/puppetdb,highb/puppetdb,mullr/puppetdb,waynr/puppetdb,highb/puppetdb,wkalt/puppetdb,mullr/puppetdb,ajroetker/puppetdb,ajroetker/puppetdb,waynr/puppetdb,grimradical/puppetdb,wkalt/puppetdb,highb/puppetdb,johnduarte/puppetdb,puppetlabs/puppetdb,kbarber/puppetdb,mullr/puppetdb,highb/puppetdb,rbrw/puppetdb,wkalt/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,johnduarte/puppetdb,kbrezina/puppetdb,puppetlabs/puppetdb,ajroetker/puppetdb,shrug/puppetdb