deploy: Remove redundant gunicorn hooks file

Remove the gunicorn hooks file from snf-deploy, since snf-webproject has
been updated to install it instead.
webproject: Reset worker_age on gunicorn reload

Make sure to reset server.worker_age on gunicorn reload, so that the
post_fork gunicorn hook works as intended.
stats: Aggregate network traffic from every iface

Fixes grnet/synnefo/#313
noVNC: Disable COPYRECT and prefer TIGHT_PNG

There seems to be an unresolved screen corruption issue with the Qemu
VNC COPYRECT encoding implementation. [1] Comment it out from the
client's preferred encoding list and, since Qemu VNC supports it, always
prefer TIGHT_PNG over TIGHT, for performance reasons.

[1] http://patchwork.ozlabs.org/patch/32165/
ci: Fetch webclient pkgs only if they were built
webproject: Set gunicorn log level to info

Set the gunicorn log level to info in the example Gunicorn conf file
shipped with snf-webproject.