When Glances is installed via venv, default configuration file is not used

[nicolargo]

If Glances is installed by the foo user via pip install --user glances[all].

Glances searchs in the following folders:

• /home/foo/.config/glances/glances.conf
• /etc/glances/glances.conf
• /usr/share/doc/glances/glances.conf

The default configuration file is here:

$ locate glances.conf
/home/foo/venv/share/doc/glances/glances.conf

In order to take this file into account, the -C option should be set:

/home/foo/venv/bin/glances -C /home/foo/venv/share/doc/glances/glances.conf

Expected behavor: the /home/foo/venv/share/doc/glances/glances.conf folder should be added to the list of default folders.

[nicolargo]

Done on the develop branch.