Repair mistaken commit of config.sh
This happened in commit and affects and
-PYTHONPATH="/home/chug/git/qpid-dispatch/python:/home/chug/git/qpid-dispatch/build/python:/home/chug/git/qpid-dispatch/tests:/opt/local/lib/python3.7/site-packages:/opt/local/lib64/proton/bindings/python:"
-PATH="/home/chug/git/qpid-dispatch/build:/home/chug/git/qpid-dispatch/build/tests:/home/chug/git/qpid-dispatch/build/router:/home/chug/git/qpid-dispatch/tools:/home/chug/git/qpid-dispatch/build/tools:/home/chug/git/qpid-dispatch/bin:/opt/local/sbin:/opt/local/bin:/usr/share/Modules/bin:/usr/lib64/ccache:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/home/chug/.dotnet/tools:/home/chug/bin"
-MANPATH="/home/chug/git/qpid-dispatch/build/doc/man::"
-SOURCE_DIR="/home/chug/git/qpid-dispatch"
-BUILD_DIR="/home/chug/git/qpid-dispatch/build"
-QPID_DISPATCH_HOME="/home/chug/git/qpid-dispatch"
-QPID_DISPATCH_LIB="/home/chug/git/qpid-dispatch/build/src/"
-QPID_DISPATCH_RUNNER=""
-MALLOC_CHECK_="3"
-MALLOC_PERTURB_="153"
-TSAN_OPTIONS=""
-ASAN_OPTIONS=""
-LSAN_OPTIONS=""
-export PYTHONPATH PATH MANPATH SOURCE_DIR BUILD_DIR QPID_DISPATCH_HOME QPID_DISPATCH_LIB QPID_DISPATCH_RUNNER MALLOC_CHECK_ MALLOC_PERTURB_ TSAN_OPTIONS ASAN_OPTIONS LSAN_OPTIONS
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+if [[ ! -f config.sh ]]; then
+ echo "You must source config.sh from within its own directory"
+ return
+fi
+
+export SOURCE_DIR=$(pwd)
+export BUILD_DIR=$SOURCE_DIR/${1:-build}
+export INSTALL_DIR=$SOURCE_DIR/${2:-install}
+
+PYTHON_BIN=`type -P python || type -P python3`
+PYTHON_LIB=$(${PYTHON_BIN} -c "from distutils.sysconfig import get_python_lib; print(get_python_lib(prefix='$INSTALL_DIR'))")
+
+export PYTHONPATH=$PYTHON_LIB:$PYTHONPATH
+export PATH=$INSTALL_DIR/sbin:$INSTALL_DIR/bin:$SOURCE_DIR/bin:$PATH
