Fix configuration directory permissions

[bobvandevijver]

When you run gtt config for the first time, it will crash with the error below:

fs.js:932
  return binding.mkdir(pathModule._makeLong(path),
                 ^

Error: EACCES: permission denied, mkdir '/home/bobvandevijver/.gtt/frames'
    at Error (native)
    at Object.fs.mkdirSync (fs.js:932:18)
    at fileConfig.assertGlobalConfig (/usr/lib/node_modules/gitlab-time-tracker/src/include/file-config.js:86:47)
    at new fileConfig (/usr/lib/node_modules/gitlab-time-tracker/src/include/file-config.js:20:14)
    at Object.<anonymous> (/usr/lib/node_modules/gitlab-time-tracker/src/gtt-config.js:6:14)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)

which is due to missing execute permissions on the directory (tested on Debian Stretch). By adding the execute bit to the directory (and removing anonymous access), this is fixed.

[coveralls]

Coverage remained the same at 72.0% when pulling 9c78e89 on bobvandevijver:patch-1 into 1670b89 on kriskbx:master.

[coveralls]

Coverage remained the same at 72.0% when pulling 9c78e89 on bobvandevijver:patch-1 into 1670b89 on kriskbx:master.

[kriskbx]

Thanks for your contribution!