patch 7.4.2124

Problem:    diffmode test leaves files behind, breaking another test.
Solution:   Delete the files.

src/testdir/test_diffmode.vim

@@ -145,6 +145,8 @@ func Test_vert_split()
   call assert_equal(0, &cursorbind)
   call assert_equal(1, &wrap)
 
+  call delete('Xtest')
+  call delete('Xtest2')
   windo bw!
 endfunc