Update https://github.com/urfave/cli to version 1.2.0 (#6838)

From un-tagged pervious version : https://github.com/urfave/cli/compare/d86a009f5e13...master

vendor/github.com/urfave/cli/.travis.yml

@@ -1,32 +1,20 @@
 language: go
-
 sudo: false
+dist: trusty
+osx_image: xcode8.3
+go: 1.8.x
+
+os:
+- linux
+- osx
 
 cache:
   directories:
   - node_modules
 
-go:
-- 1.2.x
-- 1.3.x
-- 1.4.2
-- 1.5.x
-- 1.6.x
-- 1.7.x
-- master
-
-matrix:
-  allow_failures:
-  - go: master
-  include:
-  - go: 1.6.x
-    os: osx
-  - go: 1.7.x
-    os: osx
-
 before_script:
 - go get github.com/urfave/gfmrun/... || true
-- go get golang.org/x/tools/... || true
+- go get golang.org/x/tools/cmd/goimports
 - if [ ! -f node_modules/.bin/markdown-toc ] ; then
     npm install markdown-toc ;
   fi