tweaked config error handling

src/models/networks/model-net/loggp.c

@@ -730,7 +730,7 @@ static void loggp_configure(){
         const char * anno = anno_map->annotations[i];
         int rc = configuration_get_value_relpath(&config, "PARAMS",
                 "net_config_file", anno, config_file, MAX_NAME_LENGTH);
-        if (rc == 0){
+        if (rc <= 0){
             tw_error(TW_LOC, "unable to read PARAMS:net_config_file@%s",
                     anno);
         }
@@ -739,7 +739,7 @@ static void loggp_configure(){
     if (anno_map->has_unanno_lp > 0){
         int rc = configuration_get_value_relpath(&config, "PARAMS",
                 "net_config_file", NULL, config_file, MAX_NAME_LENGTH);
-        if (rc == 0){
+        if (rc <= 0){
             tw_error(TW_LOC, "unable to read PARAMS:net_config_file");
         }
         loggp_set_params(config_file, &all_params[anno_map->num_annos]);

src/models/networks/model-net/simplep2p.c

@@ -867,7 +867,7 @@ static void sp_read_config(const char * anno, simplep2p_param *p){
     int rc;
     rc = configuration_get_value_relpath(&config, "PARAMS", 
             "net_latency_ns_file", anno, latency_file, MAX_NAME_LENGTH);
-    if (rc == 0){
+    if (rc <= 0){
         if (anno == NULL)
             tw_error(TW_LOC,
                     "simplep2p: unable to read PARAMS:net_latency_ns_file");
@@ -878,7 +878,7 @@ static void sp_read_config(const char * anno, simplep2p_param *p){
     }
     rc = configuration_get_value_relpath(&config, "PARAMS", "net_bw_mbps_file",
             anno, bw_file, MAX_NAME_LENGTH);
-    if (rc == 0){
+    if (rc <= 0){
         if (anno == NULL)
             tw_error(TW_LOC,
                     "simplep2p: unable to read PARAMS:net_bw_mbps_file");