ofagent: Ignore unknown l2pop entry removals

l2pop can send us entry removal without the corresponding addition.
Gracefully ignore it instead of crashing.

Closes-Bug: #1357198
Change-Id: I5a0cc44ba62faf15d6fe3730a9532a3826647820
ofagent: Drop log level of tenant-triggerable events

To prevent evil tenants from flooding logs.

Closes-Bug: #1372196
Change-Id: I617e9fedf8a8c5e95c6067b716c83778d4d8cc7e
Drop sslutils and versionutils modules

The modules are not used since when we've switched to oslo.messaging.

Change-Id: Ife4298e0bb29ec15404fafe4b48545bd65e038e3
Compare subnet length as well when deleting DHCP entry

When searching for the DHCP subnet entry to delete, the existing code
compares only the subnet prefix and ignores subnet length.  This could
delete the wrong entry/entries if nested subnets are present.

Change-Id: Icf079c42adeca14ef84ec57dc45a5930fde8786d
Closes-Bug: #1362416
Merge "ofagent: Drop log level of tenant-triggerable events"
Merge "Drop sslutils and versionutils modules"
Merge "Compare subnet length as well when deleting DHCP entry"
Merge "ofagent: Ignore unknown l2pop entry removals"