BigSwitch: Stop using external locks

Changes BigSwitch server manager REST lock
to an in-memory lock since the plugin isn't
expected to run in independent processes.

Closes-Bug: #1284881
Change-Id: I2fdd5ba79a0c4b94b2b410db54a63f7c0ca47525
Remove nvplib and move utility methods into nsxlib

This patch completes the process of moving code from nvplib
to nsxlib. Utility methods such as do_request and get_all_query_pages
are transferred into nsxlib, so that nvplib can be safely removed.

Partially implements blueprint nicira-plugin-renaming

Change-Id: I43be18c89ac908ebae32b39a8508a7006b5fe328
Merge "Remove nvplib and move utility methods into nsxlib"
Merge "BigSwitch: Stop using external locks"