Scram-Sha-1 mechanism : do not send authzid if it not absolutely necessary
Some servers (ejabberd) reject the challenge if the
scram attributes a (authzid) and n (authcid) are equals
or they just don't handle the authzid.
So we just don't send it if they are the same
This fix #484
package net.java.otr4j;
public interface OtrKeyManagerStore {
public abstract byte[] getPropertyBytes(String id);
public abstract boolean getPropertyBoolean(String id, boolean defaultValue);
public abstract void setProperty(String id, byte[] value);
public abstract void setProperty(String id, boolean value);
public abstract void removeProperty(String id);
}