pgsql: Fixed auto-prepare to not try preparing statements that are not

Log Message:
-----------
Fixed auto-prepare to not try preparing statements that are not preparable. Bug
found and solved by Boszormenyi Zoltan <zb@cybertec.at>, some small adjustments
by me.

Modified Files:
--------------
    pgsql/src/interfaces/ecpg/preproc:
        ecpg.addons (r1.11 -> r1.12)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/preproc/ecpg.addons?r1=1.11&r2=1.12)
        output.c (r1.25 -> r1.26)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/preproc/output.c?r1=1.25&r2=1.26)
    pgsql/src/interfaces/ecpg/test/expected:
        preproc-autoprep.c (r1.6 -> r1.7)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/preproc-autoprep.c?r1=1.6&r2=1.7)
        preproc-autoprep.stderr (r1.6 -> r1.7)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/preproc-autoprep.stderr?r1=1.6&r2=1.7)
        preproc-autoprep.stdout (r1.1 -> r1.2)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/preproc-autoprep.stdout?r1=1.1&r2=1.2)
        sql-desc.c (r1.20 -> r1.21)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/sql-desc.c?r1=1.20&r2=1.21)
        sql-execute.c (r1.14 -> r1.15)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/sql-execute.c?r1=1.14&r2=1.15)
        sql-oldexec.c (r1.6 -> r1.7)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/sql-oldexec.c?r1=1.6&r2=1.7)
        thread-prep.c (r1.9 -> r1.10)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/thread-prep.c?r1=1.9&r2=1.10)
        thread-prep.stdout (r1.3 -> r1.4)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/thread-prep.stdout?r1=1.3&r2=1.4)
        thread-thread.stdout (r1.6 -> r1.7)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/thread-thread.stdout?r1=1.6&r2=1.7)
        thread-thread_implicit.stdout (r1.6 -> r1.7)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/thread-thread_implicit.stdout?r1=1.6&r2=1.7)
    pgsql/src/interfaces/ecpg/test/preproc:
        autoprep.pgc (r1.2 -> r1.3)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/preproc/autoprep.pgc?r1=1.2&r2=1.3)