Switching to log4J causes unresolved binding in the launcher

To reproduce:

• Remove bundle/slf4j-jdk14–1.7.21.jar
• Copy slf4j-log4j12-1.7.21.jar and log4j-1.7.21.jar
• Set LOGGING_CONFIG="-D log4j.configuration=file:///<path to log4j.properties>"
• Start the server

Whilst IDM logs correctly to the configured log4j's file, this trace shows in the console:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details. 

Any attempt to alter CLASSPATH in startup.sh ended to a severe error that impedes the logging service.

This error does not occur in 5.0, so this seems to be a regression.

Whilst this is a benign error [ it affects only the launcher ], it might still make users uncomfortable.

Note that the reason to switch to a different logging framework like log4j has benefits such as:

• Time based file rotation
• MDC availability in the log4j config, for example, logging transaction IDs on each logging trace