Add <license> section to grizzly-npn pom.xml

[dhalperi]

This is copied from https://github.com/javaee/grizzly/blob/master/pom.xml#L101

The LICENSE.txt files in each repo appear to match, although they are line-wrapped differently:

• https://github.com/javaee/grizzly/blob/master/LICENSE.txt for grizzly, is wrapped
• https://github.com/javaee/grizzly-npn/blob/master/LICENSE.txt for grizzly-npn is one-para-per-line.

[rlubke]

@dhalperi We'll need a signed OCA before this PR can be merged. Please see [1].

[1] https://github.com/javaee/grizzly-npn/blob/master/CONTRIBUTING.md

[dhalperi]

@rlubke you need my signature for copying a bit from one of your poms to another? :)

[dhalperi]

OCA sent.

[rlubke]

@dhalperi I don't make the rules and I don't want to get my virtual hand slapped again. :)

[dhalperi]

My personal OCA came through:

Hello Daniel,

my pleasure to inform you that your OCA has been approved and processed.
Now you should be able to find your name in the official list of Oracle’s
contributors at: http://www.oracle.com/technetwork/community/oca-486395.html
(once the page reloads from the server). Also your account in our bug system
has been updated to reflect the same.

<snip>

regards,
Lenka

[rlubke]

I'll fix the license text file today.