server: serialize field required as specified in TSP

fixes #246

Signed-off-by: Bernd Hufmann <bernd.hufmann@ericsson.com>

Author: bhufmann

trace-server/org.eclipse.tracecompass.incubator.trace.server.jersey.rest.core/src/org/eclipse/tracecompass/incubator/internal/trace/server/jersey/rest/core/webapp/TmfConfigParamDescriptorSerializer.java

@@ -45,7 +45,7 @@ public void serialize(ITmfConfigParamDescriptor value, JsonGenerator gen, Serial
         gen.writeStringField("keyName", value.getKeyName()); //$NON-NLS-1$
         gen.writeStringField("dataType", value.getDataType()); //$NON-NLS-1$
         gen.writeStringField("description", value.getDescription()); //$NON-NLS-1$
-        gen.writeBooleanField("isRequired", value.isRequired()); //$NON-NLS-1$
+        gen.writeBooleanField("required", value.isRequired()); //$NON-NLS-1$
         gen.writeEndObject();
     }
 }