hg: build-infra/jdk8: * Be more explicit about how to correct errors with boot-jdk.

[magnus.ihse.bursie at oracle.com]

Changeset: cae52ee8f309
Author:    ihse
Date:      2012-06-13 14:48 +0200
URL:       http://hg.openjdk.java.net/build-infra/jdk8/rev/cae52ee8f309

* Be more explicit about how to correct errors with boot-jdk.
* Remove unused variables from spec.gmk.in.

! common/autoconf/boot-jdk.m4
! common/autoconf/generated-configure.sh
! common/autoconf/spec.gmk.in