travis CI: update to go 1.7

Change-Id: Ie75074cb179a0ff357763f14a4b0bbb7677f94ad

.travis.yml

@@ -3,13 +3,13 @@ dist: trusty
 go_import_path: camlistore.org
 language: go
 go:
-  - 1.6
+  - 1.7
   - tip
 before_install:
   - sudo apt-get install -qq pkg-config fuse
   - sudo modprobe fuse
   - sudo chmod 666 /dev/fuse
   - sudo chown root:$USER /etc/fuse.conf
-install: GO15VENDOREXPERIMENT=1 go run make.go -v
-before_script: GO15VENDOREXPERIMENT=1 go build -o ./bin/devcam ./dev/devcam
-script: GO15VENDOREXPERIMENT=1 ./bin/devcam test
+install: go run make.go -v
+before_script: go build -o ./bin/devcam ./dev/devcam
+script: ./bin/devcam test