Added -r option to vstart.sh usage

The -r option was not documented in the vstart.sh script.
This Commit add a new line to the usage message to provide documentation.

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>
Added manpage for vstart.sh

Creation of a manpage for the vstart.sh utility to describe
how to use it.

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>