Filter out empty cache directory items

Framework/PythonInterface/plugins/algorithms/SNSPowderReduction.py

@@ -322,7 +322,8 @@ class SNSPowderReduction(DistributedDataProcessorAlgorithm):
         self._offsetFactor = self.getProperty("OffsetData").value
         self._outDir = self.getProperty("OutputDirectory").value
         # Caching options
-        self._cache_dirs = [os.path.abspath(me.strip()) for me in self.getProperty("CacheDir").value.split(',')]
+        self._cache_dirs = [os.path.abspath(me.strip()) for me in self.getProperty("CacheDir").value.split(',')
+                            if me.strip()]  # filter out empty elements
         self._cache_dir = self._cache_dirs[0] if self._cache_dirs else ""
         self._clean_cache = self.getProperty("CleanCache").value