Set default hgk path for hgk outside bin.

--- a/hgext/hgk.py
+++ b/hgext/hgk.py
@@ -343,6 +343,6 @@ def view(ui, repo, *etc, **opts):
     if repo.filtername is None:
         optstr += '--hidden'
 
-    cmd = ui.config("hgk", "path", "hgk") + " %s %s" % (optstr, " ".join(etc))
+    cmd = ui.config("hgk", "path", "/usr/share/mercurial/hgk") + " %s %s" % (optstr, " ".join(etc))
     ui.debug("running %s\n" % cmd)
     ui.system(cmd)