RFR 8152205: jdk.security.provider.preferred is ambiguously documented

[Anthony Scarpino]

I need a review of this very simple doc clarification.  Calling out 
jdk.security.provider.preferred as a "security property" instead of just 
a "property".

http://cr.openjdk.java.net/~ascarpino/8152205/webrev/
thanks.

Tony