Manually search HOME directory for config, don't use ~

Node 'path' can't figure out how to resolve '~', and 'fs' seems
to not figure it out either... So unfortunately, what I end up
doing is converting the HOME env variable (assuming it's present),
+ '/linux-lock-service.json', and hoping I get a valid path out of
it. WFM, but I'll keep an eye out for a better solution too.
Merge pull request #5 from caitp/fix-path-resolve

Search $HOME for '.linux-lock-service.json'