bug 934459: pip no longer supports -E
bug 934459: pip no longer supports -E

Change-Id: I2acdef113d147b7130053088d4bcf8515f61b815

openstack/networking-bigswitch,openstack/networking-bigswitch,stackforge/networking-bigswitch,wolverineav/networking-bigswitch,wolverineav/networking-bigswitch,stackforge/networking-bigswitch