fix spec for jruby - Time.now.usec supports only miliseconds
fix spec for jruby - Time.now.usec supports only miliseconds

jruby-9.1.6.0 :004 > x = Time.now
 => 2016-12-26 13:31:22 -0800
jruby-9.1.6.0 :005 > x.usec
 => 251000

Ruby 2.3 supports microseconds

2.3.3 :003 > x = Time.now
 => 2016-12-26 13:32:07 -0800
2.3.3 :004 > x.usec
 => 873611

starmammoth/rack-request-object-logger,starmammoth/rack-request-object-logger