hg: jdk/jdk: 8185898: setRequestProperty(key, null) results in HTTP header without colon in request

[michael.x.mcmahon at oracle.com]

Changeset: 0211b062843d
Author:    michaelm
Date:      2019-08-12 11:24 +0100
URL:       https://hg.openjdk.java.net/jdk/jdk/rev/0211b062843d

8185898: setRequestProperty(key, null) results in HTTP header without colon in request
Reviewed-by: chegar, dfuchs

! src/java.base/share/classes/sun/net/www/MessageHeader.java
+ test/jdk/sun/net/www/B8185898.java