Fixed an issue when USIM_DIR, NVRAM_DIR and PWDenvironement variable are not defined for NAS UE.

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@5041 818b1a75-f10b-46b9-bf7c-635c3b92a50f

openair-cn/NAS/EURECOM-NAS/src/util/memory.c

@@ -63,6 +63,9 @@ char* memory_get_path(const char* dirname, const char* filename)
     if (path == NULL) {
         path = getenv(DEFAULT_NAS_PATH);
     }
+    if (path == NULL) {
+        return NULL;
+    }
 
     /* Append non-volatile data file name */
     size_t size = strlen(path) + strlen(filename) + 1;