r.kappa: better user msg; fix var (#341)

raster/r.kappa/prt_mat.c

@@ -86,7 +86,7 @@ void prn_error_mat(int out_cols, int hdr)
 	if (ncat % out_cols)
 	    num_panels++;
 	t_rowcount = 0;
-	fprintf(fd, "\nError Matrix\n");
+	fprintf(fd, "\nError Matrix (MAP1: reference, MAP2: classification)\n");
 
 	for (at_panel = 0; at_panel < num_panels; at_panel++) {
 	    first_col = at_panel * out_cols;

raster/r.kappa/stats.c

@@ -18,7 +18,7 @@ static void die(void)
 int stats(void)
 {
     char buf[1024];
-    char mname[GNAME_MAX], rname[GMAPSET_MAX];
+    char mname[GNAME_MAX], rname[GNAME_MAX];
     const char *mmapset, *rmapset;
     int i, nl;
     size_t ns;