CheckIntegrity reconnect now uses Utility mode
CheckIntegrity reconnect now uses Utility mode

CheckIntegrity class should connect to segments
utility mode. During an integrity check failure,
it tried to reconnect in normal mode, bailing
out with a critical error. This patch addresses
this problem.

This patch relates to #3

Signed-off-by: Aitor Cedres <c291605cdc8814fa7e4ed8ab461fd6352adbcf2c@pivotal.io>

Zerpet/gpcheckintegrity,ielizaga/gpcheckintegrity