SQL api is used to determine the list of source tables affected
by a query. Before this commit, the X-Cache-Channel header set
on sql api error was an arbitrary 'table' string, now the header
is omitted, the error logged and Cache-Control and Pragma headers
are sent as an attempt to request no caching.
The code includes test for this mechanism.
It took a lot of time to produce a testcase for this as the test
config was setting srid to 4326 but not changing geom column name
thus all tiles fetched by tests returned blank (ouch!)
If the request is authenticated (with map_key) then we log as the
database owner, otherwise we log as the default user.
The default user is now "publicuser" by default.
Raises dependency on Windshaft to 0.4.9+, to get the grainstore
version allowing override of database username.
Add test for req2params function, particularly authentication,
Add test for authenticated / unauthenticated access
Sandro Santilli