Unwanted auxprop related lines in logfiles

Since I configured my mail server, I was getting the following lines
in my auth.log.  Everything was working, users had to log in to
receive or send mail, so the messages were really cluttering the
logfile.

Nov 28 00:02:39 rm-003-11 lmtpunix[1085]: sql_select option missing<br />Nov 28 00:02:39 rm-003-11 lmtpunix[1085]: auxpropfunc error no mechanism available<br />Nov 28 00:05:44 rm-003-11 postfix/smtpd[1106]: sql_select option missing<br />Nov 28 00:05:44 rm-003-11 postfix/smtpd[1106]: auxpropfunc error no mechanism available<br />Nov 28 00:06:08 rm-003-11 postfix/smtpd[1108]: sql_select option missing

I wasn’t using auxprop as the method to check passwords, I am using
saslauth.  But googling around to find a way to get rid of them
did not find a solution.  On a hunch, I uninstalled the
libsasl2-modules-sql package for my Debian version, and the lines have
stopped showing up in the authentication logfile.  Everything is
still working, so that package wasn’t needed by my setup.