LA-1626 Change OAEP to default to empty string
LA-1626 Change OAEP to default to empty string

Change RSA PKCS OAEP's mechanism class to not have a required
sourceData, and to default to empty string. This will result in a
null pointer being used, which will cause cryptoki to use the default
empty string for this parameter.

Depends on Change 7779, ID I634e0a6fef77ac951c8da18fcb599636b062360d
for that change's fixes (mainly setup.py's packages).

Change-Id: I679dd0e00f913d96268eab934ccab3ed2cec880a

gemalto/pycryptoki