Make pg_upgrade copyrights just 2010, not 2010-2010.

contrib/pg_upgrade/check.c

contrib/pg_upgrade/controldata.c

contrib/pg_upgrade/dump.c

contrib/pg_upgrade/exec.c

contrib/pg_upgrade/file.c

contrib/pg_upgrade/function.c

contrib/pg_upgrade/info.c

contrib/pg_upgrade/option.c

contrib/pg_upgrade/page.c

contrib/pg_upgrade/pg_upgrade.c

contrib/pg_upgrade/pg_upgrade.h

contrib/pg_upgrade/relfilenode.c

contrib/pg_upgrade/server.c

contrib/pg_upgrade/tablespace.c

contrib/pg_upgrade/util.c

contrib/pg_upgrade/version.c

contrib/pg_upgrade/version_old_8_3.c

contrib/pg_upgrade_support/pg_upgrade_support.c