bug 553504: Print deprecation errors only once

This adds a parameter to the printError method to print an error only
once. The printed error messages are kept in a set and printed only
if they are not present in the set.

Change-Id: Ib61d2c058382ac14b5276d0daf51235b68de11ab
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>
3 files changed