Remove LINCS prints to log file
LINCS printed RMS and max constraint deviations before and after
constraining to the log file. Since this information is not useful
for the user and it is rank-local, is it now printed to debug instead.
Note that these prints appeared after refactoring, since before null
as passed as fplog.
Also removed LINCS warning prints to the log file, since they are
rank local, so only warnings on the master rank would show up.
Now warnings are only issued to stderr.
Change-Id: Ia60446ef0c21105c9687f31329ec6d4d17e8d838