Fix compiler warning. 0 does not work on strings
diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index 9018417..369eaf6 100755
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -759,7 +759,7 @@
 	}
 	if (TLVP_PRESENT(&tp, NM_ATT_ADM_STATE)) {
 		new_state.administrative = *TLVP_VAL(&tp, NM_ATT_ADM_STATE);
-		DEBUGPC(DNM, "ADM=%02s ", nm_adm_name(new_state.administrative));
+		DEBUGPC(DNM, "ADM=%2s ", nm_adm_name(new_state.administrative));
 	}
 	DEBUGPC(DNM, "\n");