Added optional requirements for metadata amazon

Better logging of errors in metadata source files

cps/metadata_provider/amazon.py

@@ -19,7 +19,7 @@
 import concurrent.futures
 import requests
 from bs4 import BeautifulSoup as BS  # requirement
-# import lxml     #requirement for better speed
+
 try:
     import cchardet #optional for better speed
 except ImportError:

cps/search_metadata.py

@@ -49,8 +49,8 @@ for f in modules:
         try:
             importlib.import_module("cps.metadata_provider." + a)
             new_list.append(a)
-        except ImportError:
-            log.error("Import error for metadata source: {}".format(a))
+        except ImportError as e:
+            log.error("Import error for metadata source: {} - {}".format(a, e))
             pass