forward port request: 6921610: 1.6 update 17 and 18 throw java.lang.IndexOutOfBoundsException

[Weijun Wang]

Hi Joe

This bug was fixed in 6u21 and just forward ported into openjdk-7. I 
hereby request it be fixed in openjdk-6 also.

With this fix, Java can deal with abnormal LDAP server responses. I have 
two code reviewers for it.

You can see a webrev/diff/patch/changeset here:

    http://hg.openjdk.java.net/jdk7/tl/jdk/rev/95bb147c7c33

The code change is identical across JDK6, openjdk-6 and openjdk-7.

Thanks
Max