PHPC-514: Fix --with-mongodb-sasl flag
PHPC-514: Fix --with-mongodb-sasl flag

Previously the directory specified using --with-mongodb-sasl=DIR was ignored.

10gen-labs/mongo-php-driver-prototype,mongodb/mongo-php-driver,mongodb/mongo-php-driver,mongodb-labs/mongo-php-driver-prototype,derickr/mongo-php-driver,jmikola/mongo-php-driver,mongodb-labs/mongo-php-driver-prototype,mongodb/mongo-php-driver,jmikola/mongo-php-driver,derickr/mongo-php-driver-prototype,jmikola/mongo-php-driver,derickr/mongo-php-driver,mongodb/mongo-php-driver,jmikola/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,jmikola/mongo-php-driver,10gen-labs/mongo-php-driver-prototype,jmikola/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,10gen-labs/mongo-php-driver-prototype,derickr/mongo-php-driver,jmikola/mongo-php-driver-prototype,10gen-labs/mongo-php-driver-prototype,derickr/mongo-php-driver,derickr/mongo-php-driver-prototype,derickr/mongo-php-driver,jmikola/mongo-php-driver-prototype,derickr/mongo-php-driver,10gen-labs/mongo-php-driver-prototype,mongodb/mongo-php-driver,jmikola/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,jmikola/mongo-php-driver