[MONDRIAN-1914] MongOLAP not logging Agg Pipeline queries sent to MongoDB

This change sets the location of log4j.xml in a system property in OSGIBoot.  Also set is the log4j.ignoreTCL=true property, which governs whether it starts with the
classloader associated with the thread when loading classes.  TCL could cause CCEs, since the OSGI classloader should be used.
Merge pull request #1255 from mkambol/mon1914

[MONDRIAN-1914] MongOLAP not logging Agg Pipeline queries sent to MongoDB