pgsql-server: Rather than referring to src/tutorial/README, put the

Log Message:
-----------
Rather than referring to src/tutorial/README, put the build instructions
for the tutorial files right here.

Modified Files:
--------------
pgsql-server/doc/src/sgml:
query.sgml (r1.37 -> r1.38)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/doc/src/sgml/query.sgml.diff?r1=1.37&r2=1.38)