RFR: 8074064 : OCSPResponse.SingleResponse objects do not parse singleExtensions

[Jamil Nimeh]

Hello all, this review fixes an issue in OCSPResponse where it does not 
parse singleExtensions in the SingleResponse structure.  I also fixed 
two minor deviations from the OCSP.RevocationStatus interface when 
getRevocationTime and getRevocationReason are called on good responses.

Bug: https://bugs.openjdk.java.net/browse/JDK-8074064
Review: 
http://cr.openjdk.java.net/~jnimeh/reviews/8074064/webrev.01/index.html

Thank you,
--Jamil