Fix RangeError bignum too big to convert into `long' on armhf platforms
Fix RangeError bignum too big to convert into `long' on armhf platforms

On a 32-bit platform such as armhf, the original calculation for
the end date of the registry SSL certificate overflowed.
Use TimeDate to prevent this from occurring.

Closes #1390

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab