restart_required cfg-param is bool and not string

There was a break to the previous version of the configuration
paramenters API when the configurations parameters were moved to
the database. The actual type of the restart_required parameter
should be a JSON boolean value, and not a string to be compatible
with the previous configuration parameters API.

Change-Id: If45944e25a55813ddf8f80010811da04d667ca19
Closes-Bug: #1379665