* pandoradb.sql, extras/pandoradb_migrate_v3.0_to_v3.1.sql: Modified DB
schema to give a default value to start_timestamp on tgis_data, without
it as is a timestamp MySQL sets the default value as CURRENT_TIMESTAMP
and also sets the CURRENT_TIMESTAMP ON UPDATE, setting the DEFAULT
CURRENT_TIMESTAMP prevents MySQL to set the ON UPDATE CURRENT_TIMESTAMP.
git-svn-id: https://svn.code.sf.net/p/pandora/code/trunk@2273 c3f86ba8-e40f-0410-aaad-9ba5e7f4b01f
a34bcfecc1