Review existing comments and add new ones

Also clarified a statement

whipper/common/cache.py

@@ -104,8 +104,8 @@ class Persister:
         try:
             self.object = pickle.load(handle)
             logger.debug('loaded persisted object from %r', self._path)
+        # FIXME: catching too general exception (Exception)
         except Exception as e:
-            # TODO: restrict kind of caught exceptions?
             # can fail for various reasons; in that case, pretend we didn't
             # load it
             logger.debug(e)
@@ -127,7 +127,7 @@ class PersistedCache:
         try:
             os.makedirs(self.path)
         except OSError as e:
-            if e.errno != 17:  # FIXME
+            if e.errno != os.errno.EEXIST:  # FIXME: errno 17 is 'File Exists'
                 raise
 
     def _getPath(self, key):

whipper/common/program.py

@@ -297,6 +297,7 @@ class Program:
                 print('Type    : %s' % metadata.releaseType)
                 if metadata.barcode:
                     print("Barcode : %s" % metadata.barcode)
+                # TODO: Add test for non ASCII catalog numbers: see issue #215
                 if metadata.catalogNumber:
                     print("Cat no  : %s" %
                           metadata.catalogNumber.encode('utf-8'))

whipper/common/task.py

@@ -87,6 +87,7 @@ class PopenTask(task.Task):
                 return
 
             self._done()
+        # FIXME: catching too general exception (Exception)
         except Exception as e:
             logger.debug('exception during _read(): %s', e)
             self.setException(e)