Coverity analysis defect 128586: Dereference null return value

Dereference null return value

If the function actually returns a null value, a null pointer dereference will occur. Return value of function which returns null is dereferenced without checking
/src/mongo/db/commands/write_commands.cpp:1357: NULL_RETURNS 128586 Assigning: "bucketsColl" = "nullptr" return value from "lookupCollectionByNamespaceForRead".
/src/mongo/db/commands/write_commands.cpp:1360: NULL_RETURNS 128586 Attempting to access the managed object of an empty smart pointer "bucketsColl".