Log OpenJPA messages through slf4j

Currently OpenJPA log messages go to standard out and aren't captured in the main airavata.log file. Instead we should configure OpenJPA to log to slf4j. See http://openjpa.apache.org/builds/2.4.2/apache-openjpa/docs/ref_guide_logging_slf4j.html

When we do so we'll want to configure the logging of OpenJPA through the logback.xml configuration. See the list of logging channels for OpenJPA. We typically log Runtime at INFO, Tool at INFO and SQL at INFO. These would correspond to the channels

• openjpa.Tool
• openjpa.Runtime
• openjpa.jdbc.SQL