[tracker] tracker-extract: Initialize variable in EPUB extractor

[Carlos Garnacho <carlosg src gnome org>]

commit e5d0116e8ce80467c0901af13a014a8649c990a6
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Nov 28 22:03:15 2016 +0100

    tracker-extract: Initialize variable in EPUB extractor
    
    Warning introduced when trying to fix mem leaks.

 src/tracker-extract/tracker-extract-epub.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/tracker-extract/tracker-extract-epub.c b/src/tracker-extract/tracker-extract-epub.c
index 0827998..2e65e10 100644
--- a/src/tracker-extract/tracker-extract-epub.c
+++ b/src/tracker-extract/tracker-extract-epub.c
@@ -287,7 +287,7 @@ opf_xml_text_handler (GMarkupParseContext   *context,
        case OPF_TAG_TYPE_EDITOR:
        case OPF_TAG_TYPE_ILLUSTRATOR:
        case OPF_TAG_TYPE_CONTRIBUTOR: {
-               TrackerResource *contact, *artist;
+               TrackerResource *contact, *artist = NULL;
                gchar *fname, *gname, *oname;
                const gchar *fullname = NULL;
                gchar *role_uri = NULL;