Updated debian/config/searchplugins.conf accordingly

Closes #12545

rm: make-rhc because it produces ssl error and does not work.

It produces ssl error if the following command has been used:

     $ rhc setup

See merge request !141

We rebrand it anyways. Also, removed the non-ssl one

Remove make-ruby1.9.1 helper

The helper is unnecessary since the file `gserver.rb` has a proper license header.

See merge request !122

linux-lts-utopic: Added CONFIG_DELL_RBTN=m

The package was failing to build due to that configuration.

I'm not sure why we didn't inherit this configuration from ubuntu kernel config, but adding it to config.common.trisquel does the work.

See merge request !131

import rhc from Ubuntu vivid

In this commit I imported `rhc` package from Ubuntu vivid into Trisquel. rhc is the program used for OpenShift.com.

Installing rhc using RubyGems will cause package conflicts, so the best way to solve this issue and improve the stability of the distro is importing rhc from Ubuntu vivid.

I tested the program and it works with no conflicts on Trisquel Belenos.

See merge request !133

libxfce4ui: Change vendor info

Fixes <http://trisquel.info/en/issues/15432>.

See merge request !130

linux-meta-lts-vivid: remove linux-firmware references

This fixes #15357

See merge request !128

update .gitignore to exclude backup files

See merge request !136

Abrowser: made about:abrowser the home page, disabled dns prefetch, disabled config button on newtab

gfxboot-theme-ubuntu: update package for trusty

See merge request !120

debian/rules passes value of XFVENDOR to the package's configure script
as the value of the "--with-vendor-info" option.  This sets the string
in the "distributed by" message in the xfce4-about program.

debian/vendorinfo also needs to be changed because debian/rules installs
this file to /usr/share/xfce4/vendorinfo if the value of XFVENDOR is not
"Xubuntu".

Fixes issue #15432.