[Fiware-tech-help] [Chp - Security][Identity Management] Update package list before installing new packages

[David Muriel]

As the installation guide is made for an Ubuntu 12.04 LTS server, it
is possible that there are new versions of the packages that the user
need to install as dependencies for the platform, so it is recommended
to update the package list prior to begin the installation of the
required packages. Add the "apt-get update" command as the first
command to run when installing the dependencies.