[gnumeric] xlsx: don't compare namespace prefix directly.

[Morten Welinder <mortenw src gnome org>]

commit e5d732bf16fe5230572f8cf55f4849cb4f80414f
Author: Morten Welinder <terra gnome org>
Date:   Tue Mar 3 07:23:27 2015 -0500

    xlsx: don't compare namespace prefix directly.
    
    r:embed could be foo:embed when reading another file.

 plugins/excel/xlsx-read-drawing.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plugins/excel/xlsx-read-drawing.c b/plugins/excel/xlsx-read-drawing.c
index ffbbc79..18c40bb 100644
--- a/plugins/excel/xlsx-read-drawing.c
+++ b/plugins/excel/xlsx-read-drawing.c
@@ -3043,7 +3043,7 @@ xlsx_blip_start (GsfXMLIn *xin, xmlChar const **attrs)
        XLSXReadState *state = (XLSXReadState *)xin->user_state;
        g_return_if_fail (GNM_IS_SO_IMAGE (state->so));
        for (; attrs != NULL && attrs[0] && attrs[1] ; attrs += 2)
-               if (!strcmp (attrs[0], "r:embed")) {
+               if (gsf_xml_in_namecmp (xin, attrs[0], XL_NS_DOC_REL, "embed")) {
                        GsfOpenPkgRel const *rel = gsf_open_pkg_lookup_rel_by_id (
                                gsf_xml_in_get_input (xin), attrs[1]);
                        GsfInput *input = gsf_open_pkg_open_rel (