Fixed parsing of parameters. Added regression test for this.

src/interfaces/ecpg/ChangeLog

src/interfaces/ecpg/preproc/Makefile

src/interfaces/ecpg/preproc/preproc.y

src/interfaces/ecpg/test/expected/sql-fetch.c

src/interfaces/ecpg/test/expected/sql-fetch.stderr

src/interfaces/ecpg/test/expected/sql-fetch.stdout

src/interfaces/ecpg/test/sql/fetch.pgc