log4j 1.2.x: Make munged log4j 1.2 builds warning-clean

[apjanke]

Get the munged log4j 1.2.15 and 1.2.17 builds as warning-clean as you can.

Items

• [ ] Javadoc warnings about missing tags.
• [ ] "Unchecked/unsafe operations" warnings.
• [ ] That "trailing varargs arg" warning.
• [ ] All deprecated-API-usage warnings, hopefully.
• [ ] The "http://0.0.0.0" maven default http blocker warning.