validation: don't use unqualified imports for gocheck

Related to #330.
app: don't use unqualified imports for gocheck

Related to #330.
db: don't use unqualified imports for gocheck

Related to #330.
errors: don't use unqualified imports for gocheck

That was easy :-)

Related to #330.
fs, fs/testing: don't use unqualified imports for gocheck

Related to #330.
git: don't use unqualified imports for gocheck

Related to #330.
heal: don't use unqualified imports for gocheck

Related to #330.
queue: don't use unqualified imports for gocheck

Related to #330.
safe: don't use unqualified imports for gocheck

Related to #330.
service: don't use unqualified imports for gocheck

Related to #330.
repository: don't use unqualified imports for gocheck

Related to #330.
log: don't use unqualified imports for gocheck

Related to #330.
provision/local: add license header to files
provision/local: don't use unqualified imports for gocheck

Related to #330.
provision/juju: don't use unqualified imports for gocheck

Related to #330.
collector: don't use unqualified imports for gocheck

Related to #330.
auth: don't use unqualified imports for gocheck
api: don't use unqualified imports for gocheck

Related to #330.
api: remove unused Checker
cmd: don't use unqualified imports in gocheck

Related to #330.