[9] RFR 8177569: keytool should not warn if signature algorithm used in cacerts is weak

[Weijun Wang]

Please take a review at

   http://cr.openjdk.java.net/~weijun/8177569/webrev.00/
Since our implementation of CertPath validation does not check for the 
signature algorithm of a root CA, keytool should not warn about its 
weakness either.

Thanks
Max