Previously, jstats_callback used drupal_write_record to insert the
record into the {jstats_acceslog} table: due to Schema API internals,
this meant that the whole schema was loaded, and
DrupalCacheArray::__destruct was trying to save it to the cache
when all the objects get destructed by PHP. However, the request
never went farther than DRUPAL_BOOTSTRAP_DATABASE, which means that
lock.inc isn't loaded, so lock_acquire isn't defined.

With this patch, jstats_callback now simply does a straight db_insert,
bypassing Schema API and thus fixing the problem.

It should also have a positive impact on performance: the old code
triggered the loading of all the .install file to build the schema,
that doesn't happen anymore.

D7 needs DRUPAL_ROOT to be defined prior to bootstraping, but that
was missed during the 7.x port.

Mike Carper authored Jan 18, 2012 and DeFr committed Jan 18, 2012

Close the client connection before bootstraping Drupal and logging
the request, which improves the perceived performance.

drupal_json was renammed to drupal_json_output in D7, fix it to
avoid a Fatal error at the end of the request processing.

Adrian Rollett authored Jan 16, 2012 and DeFr committed Jan 16, 2012

Tweak the admin screen path to conform to the Drupal 7 style, and
add a core = 7.x to the .info to be able to use the module straight
from a git checkout.