haskell-postgresql-simple: disable 'doCheck' to avoid test suite failure

Test suite test: RUNNING...
test: SqlError {sqlState = "", sqlNativeError = -1, sqlErrorMsg = "could not connect to server: No such file or directory\n\tIs the server running locally and accepting\n\tconnections on Unix domain socket \"/tmp/.s.PGSQL.5432\"?\n"}
Test suite test: FAIL
Test suite logged to: dist/test/postgresql-simple-0.2.4.1-test.log
0 of 1 test suites (0 of 1 test cases) passed.