[LNT] Fix sql index name collision

[thopre]

Summary

As revealed by the exception printing failure prior to the previous
commit, sqllite throws an error when creating the index for the
RegressionID field for the NT and link testsuite schemas since they have
the same name. This commit adds the testsuite schema to the index name
to avoid this collision.

[PrzemekWirkus]

LGTM

[thopre]

Committed as a99f86119a7c5efbe3af20511ba0bd4f9fa24355

lnt/server/db/migrations/upgrade_15_to_16.py

 """This upgrade adds a index on the fieldchange start order, to optimize the deduplication query that is
 pretty slow.
 """
 
 import sqlalchemy
 from sqlalchemy import Index, select
 from lnt.server.db.migrations.util import introspect_table
 from lnt.util import logger
 
 
 def _mk_index_on(engine, ts_name):
     fc_table = introspect_table(engine, "{}_FieldChangeV2".format(ts_name))
 
-    fast_fc_lookup = Index('idx_fast_fieldchange_lookup', fc_table.c.StartOrderID)
+    fast_fc_lookup = Index('{}_idx_fast_fieldchange_lookup'.format(ts_name), fc_table.c.StartOrderID)
     try:
         fast_fc_lookup.create(engine)
     except (sqlalchemy.exc.OperationalError, sqlalchemy.exc.ProgrammingError) as e:
         logger.warning("Skipping index creation on {}, because of {}".format(fc_table.name, e))
 
 
 def upgrade(engine):
     """Add an index to FieldChangeV2 for each fo the test-suites.

lnt/server/db/migrations/upgrade_16_to_17.py

 """This upgrade adds a index on the RegressionIndicator.regression_id because we often lookup
 indicators by regression.
 """
 
 import sqlalchemy
 from sqlalchemy import Index, select
 from lnt.server.db.migrations.util import introspect_table
 from lnt.util import logger
 
 
 def _mk_index_on(engine, ts_name):
     fc_table = introspect_table(engine, "{}_RegressionIndicator".format(ts_name))
 
-    fast_fc_lookup = Index('idx_fast_ri_lookup', fc_table.c.RegressionID)
+    fast_fc_lookup = Index('{}_idx_fast_ri_lookup'.format(ts_name), fc_table.c.RegressionID)
     try:
         fast_fc_lookup.create(engine)
     except (sqlalchemy.exc.OperationalError, sqlalchemy.exc.ProgrammingError) as e:
         logger.warning("Skipping index creation on {}, because of {}".format(fc_table.name, e))
 
 
 def upgrade(engine):
     """Add an index to FieldChangeV2 for each fo the test-suites.