Update requirements.txt
Update requirements.txt

Fixes this error when running on Ubuntu 15.10

AttributeError: 'module' object has no attribute 'PROTOCOL_SSLv3'
hauxir/OpenBazaar-Server,tyler-smith/OpenBazaar-Server,tomgalloway/OpenBazaar-Server,cpacia/OpenBazaar-Server,tomgalloway/OpenBazaar-Server,cpacia/OpenBazaar-Server,OpenBazaar/Network,tyler-smith/OpenBazaar-Server,OpenBazaar/OpenBazaar-Server,saltduck/OpenBazaar-Server,saltduck/OpenBazaar-Server,tyler-smith/OpenBazaar-Server,OpenBazaar/Network,hauxir/OpenBazaar-Server,tomgalloway/OpenBazaar-Server,OpenBazaar/Network,cpacia/OpenBazaar-Server,saltduck/OpenBazaar-Server,hauxir/OpenBazaar-Server,OpenBazaar/OpenBazaar-Server,OpenBazaar/OpenBazaar-Server