Fix issues with db pooling

Fixes bug 1157045

In addition to this a cast is used instead of a call for the
report update.

Change-Id: I1b0ea5b18b3d75dc3d047975b234275420af189c
adding parameter to configure QueuePool in SQLAlchemy

This patch introduces the parameter sqlalchemy_pool_size.
The parameter is used to configure the QueuePool, created
in configure_db(). At the moment the configuration of the
pool is only possible when using eventlet's db_pool for
MySQL (sql_dbpool_enable = True).

Change-Id: I64dec2863c1ee88215ef9b28054ba3bfaafa3b32
fixes: bug #1158235
Fix race condition in dhcp agent

This patch fixes a race condition that can happen in the dhcp agent when
a subnet is created and then a host route is then immediately added to that
subnet following a subnet.update.end notification. The race condition occurs
in refresh_dhcp_helper() where self.enable_dhcp_helper() gets called twice
since the first call had not completed self.cache.put(network). This same race
condition can also occur in the other events so lockutils.synchronized() is
added to synchronize those code segments as well.

Fixes bug 1155748

Change-Id: I2ff52adc3dfebddd6d9c15d5dc79aa65be107179
NVP metadata access - create elevated context once

Bug 1155051

This is a follow-up patch which fixes a problem with elevated
context not being passed to subroutines.

Change-Id: Ic270d8e48075b6b58117970ab870c3fb3962d93b
Imported Translations from Transifex

Change-Id: Ib20d6e551d180d84c4246a9e9684f09d5a018312
Merge "Imported Translations from Transifex"
Merge "adding parameter to configure QueuePool in SQLAlchemy"
Merge "Fix issues with db pooling"