ProjectRepairer: Use rsync --progress instead of -P

'-P' is '--partial --progress'. When a transfer is aborted, '--partial'
renames the temporary file rsync was streaming into onto the final
destination name, leaving a truncated file where a complete one is
expected.

Keep '--progress' for the transfer output and let rsync discard its
temporary file on failure.

Change-Id: Icb4c37c5dfc950e1472447597a9cfade3bd97765