RFR [9] 8160993: Fix headers in the java/net/http package

[Chris Hegarty]

This is a change fix the license headers in the java/net/http package.
There was a cut'n'paste error that mostly missed the last line of
the header. Also, I added a new line after the header consistently
in every file. As well as a few places that had other minor issues.

http://cr.openjdk.java.net/~chegar/8160993/jdk.patch
https://bugs.openjdk.java.net/browse/JDK-8160993

-Chris.