Fix bug #17288 with inserting left truncation glyph under linum-mode.

 src/xdisp.c (insert_left_trunc_glyphs): Ensure the left truncation
 glyph is written to TEXT_AREA of the temporary glyph_row.

src/ChangeLog

+2014-04-18  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (insert_left_trunc_glyphs): Ensure the left truncation
+	glyph is written to TEXT_AREA of the temporary glyph_row.
+	(Bug#17288)
+
 2014-04-18  Paul Eggert  <eggert@cs.ucla.edu>
 
 	* emacs.c (close_output_streams): Don't clear and restore errno.

src/xdisp.c

@@ -18688,6 +18688,7 @@ insert_left_trunc_glyphs (struct it *it)
   truncate_it.current_x = 0;
   truncate_it.face_id = DEFAULT_FACE_ID;
   truncate_it.glyph_row = &scratch_glyph_row;
+  truncate_it.area = TEXT_AREA;
   truncate_it.glyph_row->used[TEXT_AREA] = 0;
   CHARPOS (truncate_it.position) = BYTEPOS (truncate_it.position) = -1;
   truncate_it.object = make_number (0);