Description of problem:

The default login_process_size for dovecot is 32MB.  

This is no longer enough on x86-64, where dovecot's imap-login crashes while
trying to mmap /lib64/libsepol.so.1.

Version-Release number of selected component (if applicable):

dovecot-1.0-1.2.rc15.el5

How reproducible:

Try to use dovecot on x86-64.

Additional info:

Raising the limit to something large makes dovecot work again.  However, a
package update does not override old defaults in a config file the user edited.  

We will probably need to increase the default limit to 128MB, so a system
upgrade does not suddenly break dovecot for existing users.