try to fix coveralls in .travis.yml

Author: Jon Perritt

.travis.yml

@@ -1,16 +1,18 @@
 language: go
+sudo: false
 install:
   - go get golang.org/x/crypto/ssh
   - go get -v -tags 'fixtures acceptance' ./...
 go:
   - 1.4
   - 1.5
   - tip
+env:
+- COVERALLS_TOKEN=2k7PTU3xa474Hymwgdj6XjqenNfGTNkO8
 script: script/cibuild
 after_success:
-  - go get golang.org/x/tools/cmd/cover
   - go get github.com/axw/gocov/gocov
   - go get github.com/mattn/goveralls
-  - export PATH=$PATH:$HOME/gopath/bin/
-  - goveralls 2k7PTU3xa474Hymwgdj6XjqenNfGTNkO8
-sudo: false
+  - if ! go get github.com/golang/tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
+script:
+  - $HOME/gopath/bin/goveralls