Fix race condition that caused segfaults in imap and xmpp as seen on
drwxr-xr-x - citadel
drwxr-xr-x - contrib
drwxr-xr-x - ctdlphp
drwxr-xr-x - ctdlsalearn
drwxr-xr-x - ctdlsh
drwxr-xr-x - libcitadel
drwxr-xr-x - webcit