syslog-ng: Improved initscript VERBOSE handling.

The messages echoed when starting and stopping syslog-ng are currently
printed regardless of the setting of VERBOSE.  Adjust the initscript so
they're only printed when VERBOSE is enabled.

Signed-off-by: Richard Tollerton <rich.tollerton@ni.com>
Signed-off-by: Ben Shelton <ben.shelton@ni.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>