Propagate parse errors correctly

opam-file-format has not required a change since opam 2.1, which causes
it to report parse errors when opam-version is > 2.1 using a signal.
opam was using the format version instead of the client version to
determine if these errors are actually parse errors, and was therefore
reporting an unsupported format instead of a parse error.

src/format/opamFile.ml

@@ -1171,7 +1171,7 @@ module SyntaxFile(X: SyntaxFileArg) : IO_FILE with type t := X.t = struct
     let catch_future_syntax_error = function
     | {file_contents = [{pelem = Variable({pelem = "opam-version"; _}, {pelem = String ver; _}); _ };
                         {pelem = Section {section_kind = {pelem = "#"; _}; _}; pos}]; _}
-      when OpamVersion.(compare (nopatch (of_string ver)) (nopatch X.format_version)) <= 0 ->
+      when OpamVersion.(compare (nopatch (of_string ver)) (nopatch OpamVersion.current)) <= 0 ->
         raise (OpamPp.Bad_version (Some pos, "Parse error"))
     | opamfile -> opamfile
 

tests/reftests/pin.test

@@ -301,14 +301,14 @@ echo GARBAGE>>"$1"
 # Return code 30 #
 ### sh junk.sh pin-at-two-two/pin-at-two-two.opam
 ### opam install ./pin-at-two-two
-[ERROR] In ${BASEDIR}/pin-at-two-two/pin-at-two-two.opam:
-        unsupported or missing file format version; should be 2.0 or older
+[ERROR] At ${BASEDIR}/pin-at-two-two/pin-at-two-two.opam:11:0-11:0::
+        Parse error
 [ERROR] Strict mode: aborting
 # Return code 30 #
 ### sh junk.sh pin-at-two-three/pin-at-two-three.opam
 ### opam install ./pin-at-two-three
-[ERROR] In ${BASEDIR}/pin-at-two-three/pin-at-two-three.opam:
-        unsupported or missing file format version; should be 2.0 or older
+[ERROR] At ${BASEDIR}/pin-at-two-three/pin-at-two-three.opam:11:0-11:0::
+        Parse error
 [ERROR] Strict mode: aborting
 # Return code 30 #
 ### sh junk.sh pin-at-future/pin-at-future.opam