Cleanup and more tests for db.api methods

New tests for methods:

 backup_*
 quota_*
 reservation_*
 snapshot_*
 transfer_*
 volume_*

Removed unnecessary methods:

 quota_usage_create
 volume_metadata_get_item
 snapshot_metadata_get_item
 volume_type_extra_specs_get_item
 exact_filter

Improved coverage of existing tests.

Improved ModelsObjectComparatorMixin.

blueprint: db-api-tests

Change-Id: Ia2a3845f27a7b4b08fd8a16c6010513d213e642f
Provide user with more information on quota fail

Provide the user with useful information when a snapshot or volume
create fails because it would cause the user to exceed available quota.
Specifically report the user's current gigabyte usage and quota
allocations.

Closes-Bug: #1235148

Change-Id: Ib4c5dbcbd172c69834c2824791af755380f38e01
VMware: Re-create session for RetrievePropertiesEx

When RetrievePropertiesEx API is called after session timeout, the driver
does not re-create session automatically.

This is a regression caused when moving from RetrieveProperties to
RetrievePropertiesEx API.

Fixes bug: 1235187

Change-Id: I8a1e2452dfb3029365d59eae7850d1a9363b25f0
Drop conf_key_mgr warning message!

By default ConfKeyManager logs tons of WARNING message stating
that it isn't production ready...

Given that it is currently the only Cinder key manager option
which can be used/selected I don't think repeatedly logging
warnings is helpful. Lets just drop the warning message
for now and when a good "production ready" cinder key manager
implementation is implemented perhaps we can re-add a warning to
this class (hopefully making the production ready impl the default).

Change-Id: Id1fdddc20a963f9fa4749ad57f355cd83d0e14e3
Closes-Bug: #1236459
Ignore H803 from Hacking.

H803 checks for a period in commit messages, something the community
clearly rejected as a sensible check: periods in commit messages
should neither be rejected or required.

Change-Id: I754e10ca01b3e6f8c6482e1bcd4c2e2ca8c1cfc9
Nexenta iSCSI driver fix _lu_exists

Catch "does not exist" exception of NMS scsidisk lu_exists method.

Change-Id: I082b588dfbf54efec68a9affc76466097765b6db
Closes-Bug: #1236626
Merge "Ignore H803 from Hacking."
Merge "Drop conf_key_mgr warning message!"
Merge "Cleanup and more tests for db.api methods"
Imported Translations from Transifex

Change-Id: I8b4e6122ec5dfa64f749a73e6ccf0b777acdd4bc
remove unused methods in driver.Scheduler

cinder.scheduler.host_manager.HostManager doesn't have get_host_list()
and get_service_capabilities(). But we don't catch the AttributeError
by them. Therefore, get_host_list() and get_service_capabilities() in
cinder.scheduler.driver.Scheduler have not been used.

Also, get_host_list() and get_service_capabilities() in
cinder.scheduler.manager.SchedulerManager have not been used.

Change-Id: I402cf068612866649cc8645391eff38fca56f634
Closes-Bug: #1236723
Merge "VMware: Re-create session for RetrievePropertiesEx"
Merge "Imported Translations from Transifex"
Merge "remove unused methods in driver.Scheduler"
Utilizes assertIsNone and assertIsNotNone

Using assertEqual/assertNotEqual to test if an element
is or is not None is too python2.4.
Our unit testing framework supports assertIsNone and assertIsNotNone
which were created for these types of tests.

Change-Id: I2e430e87dd0222b194a84f2928ad36aac26aaba6
Imported Translations from Transifex

Change-Id: I68cbee28565b1b4bd0352a4d769744cab28b71a0
Merge "Provide user with more information on quota fail"
Merge "Utilizes assertIsNone and assertIsNotNone"