app: fix some golint warning

Others are not worth fixing.
api: fix some golint warnings

I don't care about the remaining warnings.
cmd: fix variable name
cmd: fix some golint warnings
cmd/crane: update code to match new cmd packag
cmd/tsuru-base: fix code that depend on the cmd package

Some types changes :-)
cmd/tsuru: fix code related to the cmd package
cmd/tsuru-admin: fix code related to the cmd package
cmd/tsr: fix some golint warnings
cmd/tsuru-base: fix some golint warnings
db: fix golint warning in test
errors: fix golint warning
exec/testing: fix golint warning
fs/testing: fix golint warning
git: fix some golint warnings
log: fix golint warning
provision/docker: fix golint warnings
provision/juju: fix golint warnings
provision/lxc: fix golint warning
queue: fix golint warnings