Add configurable http_timeout parameter for Cisco N1K

http_timeout is a constant defined in the code. This
change makes it configurable by providing it as an
option in the config file.

DocImpact

Closes-Bug: #1332290
Change-Id: I429dd9efa43f6a596933359f4627a7761411e621
Fix OVSBridge.get_port_ofport to handle empty output

Previously ovs_lib.OVSBridge.get_port_ofport() was not handling the
case where db_get_val() was returning None when no output was recieved
from ovs-vsctl.  This patch ensures that the TypeError that results
from this condition is appropriately handled.

Change-Id: I168eb0f2c6f0cb98a3eb3e118972bbaf0383ff89
Partial-bug: #1336172
Imported Translations from Transifex

Change-Id: I194cb4f511cf05b70f2bffaeb3d4daee24e46993
Merge "Fix OVSBridge.get_port_ofport to handle empty output"
Updated from global requirements

Change-Id: If26b2e9b875f8cae0af1cf66607ef1efb8dd429c
Merge "Add configurable http_timeout parameter for Cisco N1K"
Merge "Updated from global requirements"
Merge "Imported Translations from Transifex"