Fix unpromoted test

Author: panglesd

test/sources/include_in_expansion.t/run.t

@@ -1,8 +1,6 @@
 Checking that source parents are kept, using include.
 
   $ odoc compile -c module-a root.mld
-  ERROR: Failed to parse child reference: Unrecognized kind: srctree
-  [1]
 
   $ ocamlc -c -o b.cmo b.ml -bin-annot -I .
   $ ocamlc -c -o main__A.cmo a.ml -bin-annot -I .