The current is printer not refreshed when selected.

Every time a printer is selected we have to refresh it by telling
the print service to stop tracking the previously selected printer
if such and start tracking the current one. As a result of start
tracking the print service has to give us the capabilities too. A
previous patch caused a regression and we do not refresh printers
when needed.

bug:10898968

Change-Id: I9d5413e324fdb8856ef61849d36a161470eb204d