rtpgstpay: Set DELTA_UNIT flag when appropriate

When used in combination with a rtponviftimestamp element
downstream, forwarding this flag ensures it gets correctly
serialized in the ONVIF header extension.
14 jobs for gstpay-delta-flag in 84 minutes and 6 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Preparation
passed #214766
gst indent

00:00:36

passed #214765
manifest

00:00:31

 
  Build
passed #214767
build fedora x86_64

00:08:54

passed #214768
build nodebug fedora x86_64

00:08:38

 
  Test
passed #214854
check fedora

00:06:35

passed #214770
integration testsuites fedora

00:12:37

failed #214769
check fedora

00:05:21

 
  Full Builds
passed #214772
build cerbero android universal

00:21:11

passed #214773
build cerbero cross win32

00:12:10

passed #214774
build cerbero cross win64

00:03:40

passed #214771
build cerbero fedora x86_64

00:11:09

 
  Full Tests
passed #214776
valgrind bad

00:08:18

passed #214775
valgrind good

00:25:17

 
  Apps
passed #214777
android universal examples

00:08:54