Include error stacktrace in copyright plugin

Signed-off-by: Jorge Bescos Gascon <jorge.bescos.gascon@oracle.com>

Author: jbescos

etc/config/copyright-exclude

@@ -24,6 +24,7 @@
 .zip
 .dat
 .lua
+.md
 travis.sh
 .travis.yml
 /docs/src/main/docbook/inc/modules_table_footer.src

etc/travis/travis.sh

@@ -28,7 +28,9 @@ PING_LOOP_PID=$!
 mvn -version
 
 if [ "$1" = "glassfish-copyright:check" ]; then
-    mvn $1
+    # Next line should be removed. This is only to know why does it fail.
+    mvn -e glassfish-copyright:copyright
+    mvn -e $1
 else
     mvn -e -U -B clean install $1 >> $BUILD_OUTPUT 2>&1
 fi