Made the REDACTION_PROPERTIES_PATH env var required for the build_and…

…_run_unit_tests.sh script.

build_and_run_unit_tests.sh

@@ -1,9 +1,21 @@
 #!/bin/sh
+
+# check if REDACTION_PROPERTIES_PATH is set
+if [ -z "$REDACTION_PROPERTIES_PATH" ] ; then
+    echo "REDACTION_PROPERTIES_PATH is not set"
+    exit 1
+fi
+
+# remove build directory if it exists
 if [ -d build ] ; then 
     rm -r build
 fi
+
+# build
 mkdir build 
 cd build
 cmake ..
 make
+
+# run unit tests
 ./ppm_tests