RFR 8046588: test for SO_FLOW_SLA availability does not check for EACCESS

[Michael McMahon]

Could I get this change reviewed please?

We need to check if the current process has permission to use the 
SO_FLOW_SLA
socket option as well as test if the feature is installed.
The problem would cause the new test to fail on Solaris machines with S11.2
unless running with the required privilege.

http://cr.openjdk.java.net/~michaelm/8046588/webrev.1/

This change also needs to be backported to 8u20.

Thanks,
Michael