bug: When you make a schema with 2 attributes or more the schema is generated and credential definition , but you cannot issue the credential

When you make a schema with 2 attributes or more the schema is generated and credential definition , but you cannot issue the credential.

Steps:

1. Create a new schema with more then 1 attribute
2. Create a new credential definition using the new schema
3. Try to issue the credential

Actual: The issue of credential fails Expected: The issue of credential should be possible

If you create the schema with just 1 attribute its working.

Related to : #21 (closed)

#UPDATE: It might be related with the Ledger, sometimes fails with 2 or more some times it doesn't. Its related to the schema with its generation. Different Schemas with the same data, one fails the other passes upon issuing credentials.