contrib uninstall scripts

contrib/btree_gist/Makefile

contrib/btree_gist/uninstall_btree_gist.sql

contrib/chkpass/Makefile

contrib/chkpass/uninstall_chkpass.sql

contrib/cube/Makefile

contrib/cube/uninstall_cube.sql

contrib/dblink/Makefile

contrib/dblink/uninstall_dblink.sql

contrib/earthdistance/Makefile

contrib/earthdistance/uninstall_earthdistance.sql

contrib/fuzzystrmatch/Makefile

contrib/fuzzystrmatch/uninstall_fuzzystrmatch.sql

contrib/intagg/Makefile

contrib/intagg/uninstall_int_aggregate.sql

contrib/intarray/Makefile

contrib/intarray/uninstall__int.sql

contrib/isbn_issn/Makefile

contrib/isbn_issn/uninstall_isbn_issn.sql

contrib/ltree/Makefile

contrib/ltree/uninstall_ltree.sql