Add flag to connector-init for user refresh token.
Add flag to connector-init for user refresh token.

This flag causes connector-init not to get a new user refresh
token, but to use an existing token.

Change-Id: Ib53290d3fe4053bfdf5e1245c5120daf285e826f

agoode/cloud-print-connector,avlis/cloud-print-connector,swills/cups-connector,google/cloud-print-connector,201371192/cups-connector,agoode/cups-connector,swills/cups-connector,google/cloud-print-connector,google/cloud-print-connector,201371192/cups-connector,agoode/cloud-print-connector,avlis/cloud-print-connector,avlis/cloud-print-connector,agoode/cups-connector,agoode/cloud-print-connector,agoode/cloud-print-connector,avlis/cloud-print-connector,google/cloud-print-connector