SEARCH-642: Drop id fields for cdstub and tag

These are not the unique identifiers we use and are not exposed.
For cdstub we expose unique discid, for tag unique name.

Author: reosarevok

sir/schema/__init__.py

@@ -139,7 +139,6 @@
 
 
 SearchCDStub = E(modelext.CustomReleaseRaw, [
-    F("id", "id"),
     F("title", "title"),
     F("artist", "artist"),
     F("comment", "comment"),
@@ -489,7 +488,6 @@
 
 
 SearchTag = E(models.Tag, [
-    F("id", "id"),
     F("tag", "name")
 ],
     1.5,