Fix ipfs plugin and test_ipfs

by using store(inherit=False) for the creation of a new "ipfs album" as well as
when test_ipfs creates album+items to compare with.
Or put differently: Make ipfs and test_ipfs keep the old store() behaviour for
which the plugin initially was built for.

beetsplug/ipfs.py

@@ -296,4 +296,4 @@ class IPFSPlugin(BeetsPlugin):
         self._log.info("Adding '{0}' to temporary library", album)
         new_album = tmplib.add_album(items)
         new_album.ipfs = album.ipfs
-        new_album.store()
+        new_album.store(inherit=False)

test/test_ipfs.py

@@ -87,7 +87,7 @@ class IPFSPluginTest(unittest.TestCase, TestHelper):
 
         album = self.lib.add_album(items)
         album.ipfs = "QmfM9ic5LJj7V6ecozFx1MkSoaaiq3PXfhJoFvyqzpLXSf"
-        album.store()
+        album.store(inherit=False)
 
         return album