Added support for git-stable branch (currently stable-3.1 branch) in ISPConfig update script for easier development and testing.

Define bash as a parser, some systems can have "dash" as a "sh" that will end with errors.
# /usr/local/ispconfig/server/cron_daily.sh
[: 10: root: unexpected operator
[: 10: root: unexpected operator

ensure the internal PHP scripts work even if system-wide PHP settings are set that could affect how ISPConfig would work. See FS#3293

Changed PHP-FPM socket directory from /var/run/php5-fpm to /var/lib/php5-fpm because /var/run is cleand up on reboot.

implemented the patch supplied by Jan Vansteenkiste with the latest commit

Added better error handling to vlogger script in case that the mysql database connection is not available.

Modified the update scripts to check if a download of the tar.gz has succeeded.