git: openjdk/mobile: 8230694: http.keepAlive system property is inconsistently/incorrectly documented

[duke]

Changeset: 5399449a
Author:    Daniel Fuchs <dfuchs at openjdk.org>
Date:      2019-09-06 14:04:44 +0000
URL:       https://github.com/openjdk/mobile/commit/5399449a

8230694: http.keepAlive system property is inconsistently/incorrectly documented

Trivially fixed the net-properties.html file

Reviewed-by: alanb

! src/java.base/share/classes/java/net/doc-files/net-properties.html