fix TestScript/version_buildvcs_fossil

Author: ZekeLu

src/cmd/go/testdata/script/version_buildvcs_fossil.txt

@@ -25,7 +25,7 @@ rm $GOBIN/a$GOEXE
 # If there is a repository, but it can't be used for some reason,
 # there should be an error. It should hint about -buildvcs=false.
 cd ..
-mkdir $fslckout
+mv fslckout $fslckout
 env PATH=$WORK${/}fakebin${:}$oldpath
 chmod 0755 $WORK/fakebin/fossil
 ! exec fossil help
@@ -82,6 +82,7 @@ exit 1
 -- repo/README --
 Far out in the uncharted backwaters of the unfashionable end of the western
 spiral arm of the Galaxy lies a small, unregarded yellow sun.
+-- repo/fslckout --
 -- repo/a/go.mod --
 module example.com/a