add XBPS_SYSLOG environment variable to overwrite configuration

run-tests

@@ -9,6 +9,7 @@ NPROCS=1
 if [ -r /proc/cpuinfo ]; then
 	NPROCS=$(grep ^proc /proc/cpuinfo|wc -l)
 fi
+export XBPS_SYSLOG=false
 LIBRARY_PATH=$PWD/lib LD_LIBRARY_PATH=$PWD/lib ATF_SHELL=/bin/sh kyua --variable parallelism=$NPROCS test -r result.db -k tests/xbps/Kyuafile
 rv=$?
 kyua report --verbose -r result.db