Remove unused RPC calls from n1kv plugin code

Change-Id: I75a70786827a5fd6c321b560f1f2ef02a69aa85d
Closes-Bug: #1275166
Parse JSON in ovs_lib.get_vif_port_by_id

This patch replaces regex matching of text output with parsing
of JSON output in ovs_lib.get_vif_port_by_id.
This makes the code more reliable as subtle, possibly even
cosmetic, changes in ovs-vsctl output format could cause the
regular expression match to fail.

Also, this makes the code consistent with ovs_lib.get_vif_port_set
which already uses JSON output.

Finally this patch slightly changes the behaviour of
ovs_lib.get_vif_port_by_id returning None if elements such as
mac address or ofport were not available.

Change-Id: Ia985a130739c72b5b88414a79b2c6083ca6a0a00
Closes-Bug: #1280827
Imported Translations from Transifex

Change-Id: Iacb4571f529a6697aa722fc88f0ca1b40fe61e8c
Revert "Skip a test for nicira service plugin"

This reverts commit 95807c9436be7eb34fe37289d76fb4611ab77783.

Change-Id: I03dc9bb99b8372bfa4bb05246916b856569969f7
Merge "Remove unused RPC calls from n1kv plugin code"
Merge "Imported Translations from Transifex"
Merge "Revert "Skip a test for nicira service plugin""
Merge "Parse JSON in ovs_lib.get_vif_port_by_id"