PDI-3064 - junits for regression fix

	modified:   engine/test-src/org/pentaho/di/trans/steps/mapping/MappingParametersTest.java
PDI-3064 -  Mapping / Sub-transformation doesn't pick up named parameters defined in parent if they are also defined in the subtrans

fix regresion. Mapping transformation must correctly pass variables from
parent to child transformation according to 'Inherit variable' checkbox
mode.
[PDI-10591]: NPE and exposed exception on the DI-Server/Carte status page when the repository is not correctly defined (or repositories.xml is not accessible) - exception is not logged in the pentaho.log nor any tomcat\logs

The fix consists of two minor changes:
1)In the case when the repository is not correctly defined (or repositories.xml is not accessible) the page will display the short message: Unable to connect to repository:<Repository_Id>;
2)Added logging for the exception (with full stacktrace ) into pentaho.log

There is no any changes in logic of processing data in GetStatusServlet just minor tune so there is no need in unit tests.