Remove 1024-bit default requirement from javadoc of java.security.interfaces.DSAKeyPairGenerator

The DSAKeyPairGenerator class description currently says the following:

"If no initialize method is called on a DSAKeyPairGenerator, the default is to generate 1024-bit keys, using precomputed p, q and g parameters and an instance of SecureRandom as the random bit source."

1024-bit keys are no longer recommended. Ideally, this default requirement should be removed and it should be implementation-specific as to what size keys are generated. Suggest changing this to:

"If no initialize method is called on a DSAKeyPairGenerator, the default is to generate keys of an implementation-specific size, using precomputed p, q and g parameters and an instance of SecureRandom as the random bit source. However, note that the default keysize may vary across different implementations and may change in a future version. Therefore, it is recommended to explicitly initialize the DSAKeyPairGenerator instead of relying on defaults."