loadgen Test: change test 5 from (redundant) verify to (new) compare

Signed-off-by: Mark Kampe <mark.kampe@gmail.com>
loadgen: added test case for enumerated file sequential write/verify

Signed-off-by: Mark Kampe <mark.kampe@gmail.com>
loadgen: add test cases for single file random write/verify
	 fix a bug in single file delete after verify

Signed-off-by: Mark Kampe <mark.kampe@gmail.com>