[Tracker] one bug in libtracker-gtk

[Jerry Tan <Jerry Tan Sun COM>]

When I run tracker-search-tool on solaris sparc,
I always met the problem that it tells me "Invalid or non-existant type 
was specified"

I debug it, found that some  string array are not null terminated,
when sending
it depend on compile to add NULL after it, which is not good.
if some compile does not do that, it will
so I made this patch.

and I see dbus tutorial (http://dbus.freedesktop.org/doc/dbus-tutorial.html)
its sample to Sending two array of strings, these two strings are NULL 
terminated.





Index: src/libtracker-gtk/tracker-metadata-tile.c
===================================================================
--- src/libtracker-gtk/tracker-metadata-tile.c  (revision 649)
+++ src/libtracker-gtk/tracker-metadata-tile.c  (working copy)
@@ -239,7 +239,8 @@
        "File:Size",
        "File:Accessed",
        "File:Mime",
-       "DC:Keywords"
+       "DC:Keywords",
+        NULL
 };
 
 enum {
@@ -262,7 +263,8 @@
        "Doc:PageCount",
        "Doc:WordCount",
        "Doc:Created",
-       "DC:Keywords"
+       "DC:Keywords",
+        NULL
 };
 
 enum {
@@ -288,7 +290,8 @@
        "Audio:ReleaseDate",
        "Audio:Codec",
        "File:Size",
-       "DC:Keywords"
+       "DC:Keywords",
+        NULL
 };
 
 enum {
@@ -317,7 +320,8 @@
        "Image:Flash",
        "Image:FocalLength",
        "Image:ExposureTime",
-       "DC:Keywords"
+       "DC:Keywords",
+        NULL
 };
 
 enum {
@@ -345,7 +349,8 @@
        "Video:Codec",
        "Video:Bitrate",
        "Video:Duration",
-       "DC:Keywords"
+       "DC:Keywords",
+        NULL
 };
 
 enum {