AutoConfigFlags: factorize detector description flags

Introduce a "detector" layer for the detector description flags to make sure we don't have name collisions across systems. Adjust client code accordingly.

Also remove the default values as those are already being set within the detector specific GeoDB modules.

Control/AthenaConfiguration/python/AutoConfigFlags.py

@@ -37,20 +37,21 @@ def _initializeGeometryParameters(geoTag):
     dbGeomCursor = AtlasGeoDBInterface(geoTag)
     dbGeomCursor.ConnectAndBrowseGeoDB()
 
-    # FIXME: geometry parameter names need to be unique across systems!
-    params = {}
-    params.update(CommonGeoDB.InitializeGeometryParameters(dbGeomCursor))
-    params.update(PixelGeoDB.InitializeGeometryParameters(dbGeomCursor))
-    params.update(LArGeoDB.InitializeGeometryParameters(dbGeomCursor))
-    params.update(MuonGeoDB.InitializeGeometryParameters(dbGeomCursor))
+    params = { 'Common' : CommonGeoDB.InitializeGeometryParameters(dbGeomCursor),
+               'Pixel' : PixelGeoDB.InitializeGeometryParameters(dbGeomCursor),
+               'LAr' : LArGeoDB.InitializeGeometryParameters(dbGeomCursor),
+               'Muon' : MuonGeoDB.InitializeGeometryParameters(dbGeomCursor) }
 
     return params
 
 
 @lru_cache(maxsize=4)  # maxsize=1 should be enough for most jobs
-def GetDetDescrInfo(geoTag):
-    """Query geometry DB for detector description"""
+def DetDescrInfo(geoTag):
+    """Query geometry DB for detector description. Returns dictionary with
+    detector description. Queries DB for each tag only once.
 
+    geoTag: gemometry tag (e.g. ATLAS-R2-2016-01-00-01)
+    """
     detDescrInfo = _initializeGeometryParameters(geoTag)
     detDescrInfo["geomTag"] = geoTag
     return detDescrInfo