Provide "atomic" database access for networks

Fixes bug 1093637

In the OVS and LB plugins there are cases when accessing the network
has an additional database query. The patch enables this to occur
without accessing an invalid database entry.

Change-Id: I7d4944cf3240819f23dd7b4993d6ae3cefab9dc2
Implementing string representation for model classes

We want to have meaningfull representation. This is
useful when we debug and want to see the actual
attributes of the object. The current __repr__
of those classes is the default python implementation
 and does not provide
information about the object attributes.
Solve Bug #1084231

Change-Id: I1ea5d741d2fd2da13712e0d51d2c73dfba4991cf
Solve the conflict below:
Conflicts:
	quantum/tests/unit/test_db_plugin.py
Update the configuration help for the OVS cleanup utility

Fixes the details of the deletion parameter.

Change-Id: Ia732e6012bc3eaf293697325d507ae8dfc007683
Correct exception output for subnet deletion when port is used

Fixes bug 1093754

Change-Id: I2deaced0cfc2524234ff79e39e6e7c2f757ff19f
Ensure bulk creations have quota validations

Fixes bug 1093749

The patch set also returns a proper error instead of a internal server
error when the quotas are reached.

Change-Id: Ifc74ffa8b54faa70f5558bf5263830f5e71f58ae
Raise InvalidInput directly instead of catch it

Fixes bug 1094023

Change-Id: I960b01996e33da0da5e9cd181479ebcf70d38997
Ensure allocation pools are deleted from database

Fixes bug 1091946

Change-Id: I4330f7a81e4745d5885d58fe7c8a010d18a8e004
Ensures that the dnsmasq configuration file flag is always set

Fixes bug 1094183

If the flag is not set then the default configuration file may
be used. This may be problematic in certain setups.

Change-Id: Ibd0be960779f391a198454510dd6edcbc69c149c
Merge "Raise InvalidInput directly instead of catch it"
Readjust try/catch block in quantum.api.v2.base.create()

Removed the outer try/catch block to handle all exceptions in one block.
Moved irrelevant statements out of the block

Change-Id: I5c248403b8419f664ef6f17e70a016e7c0cd4ae6
Exceptions cleanup

Ensure that the quantum exceptions in FAULT_MAP are grouped
together (this will save endless bug fixes when the server
will return 500 instead of 4xx)

Change-Id: I89581e1b6b4af3eb1803d6226686adf0b576d1e7
Merge "Exceptions cleanup"
Merge "Correct exception output for subnet deletion when port is used"
Merge "Ensure allocation pools are deleted from database"
Ensure that exception prints correct text.

Fixes bug 1095333

Change-Id: I5077108de8dacaab4bcf0d7236123f960676d591
Set default core_plugin to None

Fixes bug 1093989

Change-Id: Ib0b77994b813e6b2ec0621949371c66d66472896
Merge "Ensures that the dnsmasq configuration file flag is always set"
Merge "Implementing string representation for model classes"
Remove unused imports in agent package

Change-Id: Id0286e5e866512eb0c939515949e21a71089e542
Provider network implementation for NVP plugin.

blueprint nvp-provider-net

Implements the provider network extension support. The list of valid network
types has been updated to reflect the types supported by the nvp plugin.
This was necessary otherwise validation would have always failed.
Multiple logical switches might be associated with a quantum network; the
first logical switch will always have the same id as the quantum network.
Also now raises exception when port limit on overlay network is reached.

This patch also adds a check for the maximum number of ports on 'standard'
overlay networks, and performs some code refactoring for improving
maintanability. For instance the NVPCluster class has been moved into its own
module.

Change-Id: Ib26d327daf748cfcba9ca74e8dc2e8e89c676c2e