get-schema CHANGE reflect changes in libyang

identity value is now stored in libyang including the prefix, so in
case of getting format for the get-schema result, we have to take it into
consideration.
diff --git a/src/session_server.c b/src/session_server.c
index 277dfc3..2588a72 100644
--- a/src/session_server.c
+++ b/src/session_server.c
@@ -327,9 +327,9 @@
     }
 
     /* check format */
-    if (!format || !strcmp(format, "yang")) {
+    if (!format || !strcmp(format, "ietf-netconf-monitoring:yang")) {
         lys_print_mem(&model_data, module, LYS_OUT_YANG, NULL);
-    } else if (!strcmp(format, "yin")) {
+    } else if (!strcmp(format, "ietf-netconf-monitoring:yin")) {
         lys_print_mem(&model_data, module, LYS_OUT_YIN, NULL);
     } else {
         err = nc_err(NC_ERR_INVALID_VALUE, NC_ERR_TYPE_APP);