hg: jdk7/build: 6674232: OPENJDK=false is same as OPENJDK=true

[kelly.ohair at sun.com]

Changeset: 05809a7eb190
Author:    ohair
Date:      2008-03-18 11:01 -0700
URL:       http://hg.openjdk.java.net/jdk7/build/rev/05809a7eb190

6674232: OPENJDK=false is same as OPENJDK=true
Summary: If OPENJDK has a value, that value must be "true", empty value == undefined with GNU make.
Reviewed-by: tbell

! make/Defs-internal.gmk