test_build.sh: Allow WARNERROR to be overridden

Currently, WARNERROR is hardcoded to 'yes' which is what we want most of
the time, but there are cases (such as when building with -fanalyzer)
that we don't want it enabled, so we see the entire output of the build,
and it doesn't halt at the first error.  Removing the WARNERROR line
from the script allows the variable to be overridden from an environment
variable.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: Iea931e57f2a6992762566dc3dbaae8bb8df5b226
Reviewed-on: https://review.coreboot.org/c/flashrom/+/62745
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

test_build.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env sh
 set -e
 
-make CONFIG_EVERYTHING=yes WARNERROR=yes
+make CONFIG_EVERYTHING=yes
 
 
 builddir=out