Add HOSTNAME suggestion to VTE Configuration page

[robmv]

I have been experiencing the VTE configuration error dialog for a long time, but was able to pinpoint the fix.

When DHCP servers assign hostnames, and that hostname is received after the user has logged in, the error is shown. The problem is caused because some distributions (Fedora in my case) assign a new value for the HOSTNAME variable at /etc/profile, that means it runs at login, but if the DHCP connection is established later, for example a WiFi connection, the HOSTNAME variable isn't in sync with what the DHCP server assigned.

HOSTNAME=$(hostname) in .bashrc solves this problem.