Fix dependency problems with APT repo handling

The first issue was that Exec[apt_get_update_for_nginx] resource is only
needed if $manage_repo == true, so it was put inside the corresponding
if block.

But even inside the if-block, Exec[apt_get_update_for_nginx] could fail
when $package_source has an invalid value and no Apt::Source[nginx] is
defined, so the respective Apt::Source[nginx], if defined, will now notify
Exec[apt_get_update_for_nginx] and Exec[apt_get_update_for_nginx] will
no longer subscribe to Apt::Source[nginx].

It would probably make sense to add a call to fail() in the default case
of $package_source.
Merge pull request #155 from fpletz/fix/apt-dependency-breakage

Fix dependency problems with APT repo handling
Fix RHEL installation support
Merge pull request #158 from miguno/master

Fix RHEL installation support
regex replace / in resource::vhost Fixes #102
Merge pull request #162 from jfryman/sanitize_vhost_location

Regex replace / in resource::vhost
add travis config
validate all arrays
fix specs to cater for PR #162
fix specs for PR #158
apt modules relies on lsbdistcodename fact
check apt::source in catalog, not the file it creates

We should trust the apt module to do the right thing,
and just test that apt::source is part of the catalogue.
Fix upstream_cfg_prepend loop to put every element on a dedicated line
Merge pull request #165 from 3flex/rspec-fixes

Rspec fixes
Merge pull request #164 from 3flex/validations

Validate all arrays
Merge pull request #163 from 3flex/travis-config

Add Travis config
Merge pull request #166 from gini/fix_upstream_prepend

Fix upstream_cfg_prepend loop to put every element on a dedicated line
Adding upstream fail_timeout.
Update vhost.pp

bug fix. 
User priority for location 400-499, 501-599.
Header should have a priority lower than the others.
Merge pull request #184 from abraham1901/patch-1

Update vhost.pp