appender.cxx: Only notify in-flight condition when the count is zero.
appender.cxx: Only notify in-flight condition when the count is zero.

csuideal/log4cplus,ccpaging/log4cplus,csuideal/log4cplus,ccpaging/log4cplus,csuideal/log4cplus,ccpaging/log4cplus,csuideal/log4cplus,ccpaging/log4cplus