patch 9.0.1594: some internal error messages are translated

Problem:    Some internal error messages are translated.
Solution:   Consistently do not translate internal error messages.
            (closes #12459)
diff --git a/src/memfile.c b/src/memfile.c
index 3104259..abb7c3f 100644
--- a/src/memfile.c
+++ b/src/memfile.c
@@ -478,7 +478,7 @@
     flags = hp->bh_flags;
 
     if ((flags & BH_LOCKED) == 0)
-	iemsg(_(e_block_was_not_locked));
+	iemsg(e_block_was_not_locked);
     flags &= ~BH_LOCKED;
     if (dirty)
     {