Обсуждение: pgsql: Fix up problems in write_auth_file and parsing of the auth file.

Log Message:
-----------
Fix up problems in write_auth_file and parsing of the auth file.
In particular, make hba.c cope with zero-length tokens, which it
never did properly before.  Also, enforce rolcanlogin.

Modified Files:
--------------
    pgsql/src/backend/commands:
        user.c (r1.153 -> r1.154)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/user.c.diff?r1=1.153&r2=1.154)
    pgsql/src/backend/libpq:
        hba.c (r1.143 -> r1.144)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/hba.c.diff?r1=1.143&r2=1.144)
    pgsql/src/backend/utils/init:
        flatfiles.c (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/init/flatfiles.c.diff?r1=1.9&r2=1.10)
        miscinit.c (r1.143 -> r1.144)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/init/miscinit.c.diff?r1=1.143&r2=1.144)