hg: jdk9/dev: 8027627: Don't hardcode bash path in LOG=trace

[magnus.ihse.bursie at oracle.com]

Changeset: 0610b52412cf
Author:    ihse
Date:      2014-09-01 10:39 +0200
URL:       http://hg.openjdk.java.net/jdk9/dev/rev/0610b52412cf

8027627: Don't hardcode bash path in LOG=trace
Reviewed-by: erikj, tbell
Contributed-by: Dmitry Samersoff <dmitry.samersoff at oracle.com>

! make/common/MakeBase.gmk