BuilderUtils.py: default to more logging output

For quite a while, the build-with-autotools Open MPI nightly build on
Open MPI v5.0.0 has been failing.  It turns out that upstream PMIx
upgraded the version of Sphinx that it required, which ultimately
caused the build failure because the Sphinx version installed on
aws.open-mpi.org was too old.  Upgrading the Sphinx on
aws.open-mpi.org was easy enough.

The real issue is that the failure notification email did not include
enough logging output to reveal that the root cause of the build
failure was the Sphinx version.  As such, this commit increases the
default number of log lines included in the failure message in the
email so that this particular problem, at least, will be evident in
future emails.

Signed-off-by: Jeff Squyres <jeff@squyres.com>

Author: jsquyres

nightly-tarball/BuilderUtils.py

@@ -1,6 +1,7 @@
 #
 # Copyright (c) 2017      Amazon.com, Inc. or its affiliates.  All Rights
 #                         Reserved.
+# Copyright (c) 2024      Jeffrey M. Squyres.  All rights reserved.
 #
 # Additional copyrights may follow
 #
@@ -14,7 +15,7 @@
 def logged_call(args,
                 wrapper_args=None,
                 log_file=None,
-                err_log_len=20,
+                err_log_len=30,
                 env=None):
     """Wrapper around check_call to log output