VOL-1497 : Add more control to kv/memory access

- Added kv locking mechanism (etcd only)
- (watch) control path access whenever possible
- (watch) use a transaction for updates and merge with memory
- cleaned up vendoring
- misc changes to fix exceptions found along the way

Amendments:

- Copyright header got removed in auto-generated file
- Changed default locking to false for KV list operation
- Updated backend api to allow the passing of locking parameter

Change-Id: Ie1a55d3ca8b9d92ae71a85ce42bb22fcf1419e2c
diff --git a/vendor/github.com/gregjones/httpcache/.travis.yml b/vendor/github.com/gregjones/httpcache/.travis.yml
index b5ffbe0..597bc99 100644
--- a/vendor/github.com/gregjones/httpcache/.travis.yml
+++ b/vendor/github.com/gregjones/httpcache/.travis.yml
@@ -1,19 +1,18 @@
 sudo: false
 language: go
-go:
-  - 1.6.x
-  - 1.7.x
-  - 1.8.x
-  - 1.9.x
-  - master
 matrix:
   allow_failures:
     - go: master
   fast_finish: true
+  include:
+    - go: 1.10.x
+    - go: 1.11.x
+      env: GOFMT=1
+    - go: master
 install:
   - # Do nothing. This is needed to prevent default install action "go get -t -v ./..." from happening here (we want it to happen inside script step).
 script:
   - go get -t -v ./...
-  - diff -u <(echo -n) <(gofmt -d .)
+  - if test -n "${GOFMT}"; then gofmt -w -s . && git diff --exit-code; fi
   - go tool vet .
   - go test -v -race ./...