Build and install from GOPATH

* Rename 'vendor/src' -> 'vendor'
  * Ignore vendor/ instead of vendor/src/ for lint
* Rename 'cmd/client' -> 'cmd/ocic' to make it 'go install'able
* Rename 'cmd/server' -> 'cmd/ocid' to make it 'go install'able
* Update Makefile to build and install from GOPATH
* Update tests to locate ocid/ocic in GOPATH/bin
* Search for binaries in GOPATH/bin instead of PATH
* Install tools using `go get -u`, so they are updated on each run

Signed-off-by: Jonathan Yu <jawnsy@redhat.com>

.tool/lint

@@ -5,18 +5,18 @@ set -o nounset
 set -o pipefail
 
 for d in $(find . -type d -not -iwholename '*.git*' -a -not -iname '.tool' -a -not -iwholename '*vendor*'); do
-	gometalinter \
-		--exclude='error return value not checked.*(Close|Log|Print).*\(errcheck\)$' \
-		--exclude='.*_test\.go:.*error return value not checked.*\(errcheck\)$' \
-		--exclude='duplicate of.*_test.go.*\(dupl\)$' \
-		--exclude='cmd\/client\/.*\.go.*\(dupl\)$' \
-		--exclude='vendor\/src\/.*' \
-		--exclude='server\/seccomp\/.*\.go.*$' \
-		--disable=aligncheck \
-		--disable=gotype \
-		--disable=gas \
-		--cyclo-over=60 \
-		--dupl-threshold=100 \
-		--tests \
-		--deadline=30s "${d}"
+	${GOPATH}/bin/gometalinter \
+		 --exclude='error return value not checked.*(Close|Log|Print).*\(errcheck\)$' \
+		 --exclude='.*_test\.go:.*error return value not checked.*\(errcheck\)$' \
+		 --exclude='duplicate of.*_test.go.*\(dupl\)$' \
+		 --exclude='cmd\/client\/.*\.go.*\(dupl\)$' \
+		 --exclude='vendor\/.*' \
+		 --exclude='server\/seccomp\/.*\.go.*$' \
+		 --disable=aligncheck \
+		 --disable=gotype \
+		 --disable=gas \
+		 --cyclo-over=60 \
+		 --dupl-threshold=100 \
+		 --tests \
+		 --deadline=30s "${d}"
 done