autotest: fixed handling for wiki and xml generation

Tools/autotest/param_metadata/param_parse.py

@@ -107,7 +107,7 @@ for library in libraries:
             debug("\n Processing file '%s'" % path)
             if path.endswith('.pde'):
                 if len(vehicles) != 1:
-                    error("Unable to handle multiple vehicles with .pde library")
+                    print("Unable to handle multiple vehicles with .pde library")
                     continue
                 libraryfname = os.path.join(vehicles[0].path, path)
             else:

Tools/scripts/build_parameters.sh

@@ -5,7 +5,10 @@ set -e
 # work from either APM directory or above
 [ -d ArduPlane ] || cd APM
 
-./Tools/autotest/param_metadata/param_parse.py > param.out || exit 1
+./Tools/autotest/param_metadata/param_parse.py > param.out || {
+    echo "Parameter parsing failed"
+    exit 1
+}
 /bin/mkdir -p ../buildlogs/Parameters
 /bin/cp Parameters.wiki Parameters.html *.pdef.xml ../buildlogs/Parameters/