Fix sm crash on HUP signal

sm.c.diff

diff --git a/sm/sm.c b/sm/sm.c
index d48541e..2dcf25e 100644
--- a/sm/sm.c
+++ b/sm/sm.c
@@ -329,7 +329,7 @@ int sm_register_ns(sm_t sm, const char *uri) {
         ns_idx = xhash_count(sm->xmlns) + 2;
         xhash_put(sm->xmlns, pstrdup(xhash_pool(sm->xmlns), uri), (void *) (long) ns_idx);
     }
-    xhash_put(sm->xmlns_refcount, uri, (void *) ((long) xhash_get(sm->xmlns_refcount, uri) + 1));
+    xhash_put(sm->xmlns_refcount, pstrdup(xhash_pool(sm->xmlns_refcount), uri), (void *) ((long) xhash_get(sm->xmlns_refcount, uri) + 1));
 
     return ns_idx;
 }
@@ -341,7 +341,7 @@ void sm_unregister_ns(sm_t sm, const char *uri) {
         xhash_zap(sm->xmlns, uri);
         xhash_zap(sm->xmlns_refcount, uri);
     } else if (refcount > 1) {
-        xhash_put(sm->xmlns_refcount, uri, (void *) ((long) xhash_get(sm->xmlns_refcount, uri) - 1));
+        xhash_put(sm->xmlns_refcount, pstrdup(xhash_pool(sm->xmlns_refcount), uri), (void *) ((long) xhash_get(sm->xmlns_refcount, uri) - 1));
     }
 }