srdb1/schema: removed unique constraint from connection_idx

(cherry picked from commit d72ac166b152ca6906248d67e2605d5b283fa01e)

lib/srdb1/schema/location.xml

@@ -232,7 +232,6 @@
         <name>connection_idx</name>
         <colref linkend="server_id"/>
         <colref linkend="connection_id"/>
-        <unique/>
     </index>