Show concerned lock file when error is launched

Not a big modification, just put the concerned lockfile when the error is launched.

This permit to easily find the concerned file and delete it if needed.

Thanks.
#69: add missing variable
Merge branch 'master' of https://github.com/mimmi20/browscap-php into issue-69
update composer.lock
Merge pull request #70 from mimmi20/issue-69

Fixes #69
Merge pull request #68 from Soullivaneuh/patch-1

Show concerned lock file when error is launched