Fix arguments in `mc_unpackers`

Fixes bug introduced by a late to change to LHCb!3395 (merged) that was not mirrored in !1299 (merged).

See LHCb#189 for more info on discussion around use of output_level and bind

Hlt/Hlt2Conf/tests/options/sprucing/spruce_check.py

@@ -86,9 +86,8 @@ algs += [hlt2_decisions(process=process, stream=stream)]
 algs += [spruce_decisions(process=process, stream=stream)]
 
 # Unpack TES locations
-algs += mc_unpackers(
-    process=process, output_level=4) + unpackers(
-        process=process, output_level=4)
+algs += mc_unpackers(process=process) + unpackers(
+    process=process, output_level=4)
 
 ApplicationMgr(TopAlg=algs)