Fixes postgres database issue when using encoding: UTF8 on ubuntu 12.04

Sets the ENV['LANGUAGE'] to en_US.UTF-8 by default 

avoids error
```
FATAL: PG::Error: postgresql_database[DB_NAME] (databox::postgresql line
36) had an error:
PG::Error: ERROR:  encoding UTF8 does not match locale en_US
DETAIL:  The chosen LC_CTYPE setting requires encoding LATIN1.
```
on ubuntu 12.04 and below - might be worth adding since 12.04 is LTS - https://wiki.ubuntu.com/LTS