Commit 36b59c001c introduces
DIB_DEBUG_TRACE, to be checked in element scripts for enabling tracing.
In the aforementioned conversion, few scripts were left with
unconditional "set -x" calls: remove them, changing the default value
for unset DIB_DEBUG_TRACE from 0 to 1, to retain their older behaviour
(as it was done in 36b59c001c too).
Change-Id: I3d1a9290021bf63de7d4e7752e809852e784ac8b