8004234: Downgrade normative references to ${java.home}/lib/security/krb5.conf

Reviewed-by: alanb, weijun

src/share/classes/javax/security/auth/kerberos/package.html

@@ -43,10 +43,15 @@ questions.
 
     You can provide the name of your default realm and Key Distribution
     Center (KDC) host for that realm using the system properties
-    java.security.krb5.realm and java.security.krb5.kdc. Alternatively, you 
-    can provide an MIT style configuration file called krb5.conf in
-    <java-home>/lib/security. If you place this file elsewhere, you can
-    indicate that location via the system property java.security.krb5.conf.<p>
+    {@code java.security.krb5.realm} and {@code java.security.krb5.kdc}.
+    Both properties must be set.
+    Alternatively, the {@code java.security.krb5.conf} system property can
+    be set to the location of an MIT style {@code krb5.conf} configuration
+    file. If none of these system properties are set, the {@code krb5.conf}
+    file is searched for in an implementation-specific manner. Typically,
+    an implementation will first look for a {@code krb5.conf} file in
+    {@code <java-home>/lib/security} and failing that, in an OS-specific
+    location.<p>
 <!--
 <h2>Package Specification</h2>