remove 'exec' from 'script' attribute

Author: Jon Perritt

.travis.yml

@@ -15,6 +15,6 @@ before_install:
   - go get github.com/pierrre/gotestcover
   - if ! go get github.com/golang/tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
 script:
-  - exec $HOME/gopath/bin/gotestcover -v -tags=fixtures -coverprofile=cover.out ./...
+  - $HOME/gopath/bin/gotestcover -v -tags=fixtures -coverprofile=cover.out ./...
 after_success:
   - $HOME/gopath/bin/goveralls -service=travis-ci -coverprofile=cover.out