Remove unnecessary strlen() call

	modified:   plugins/imkmsg/kmsg.c
Fix message read buffer size

	modified:   plugins/imkmsg/kmsg.c
Fix tv.tv_usec computation to avoid rounding

	modified:   plugins/imkmsg/kmsg.c
Do not exit when messages get overwritten in the circular buffer

	modified:   plugins/imkmsg/kmsg.c
Removed unnecessary setting of console log level

	modified:   plugins/imkmsg/kmsg.c