afscp: Fix -s option for writes

afscp: Fix -s option for writes

When writing to AFS with afscp, the -s option was sleeping before any
StoreData RPCs actually got issued to the fileserver. Move the sleep
to after we have done one rx_Read/rx_Write, so we sleep after starting
to contact the fileserver, to make sleeping while writing more
consistent with sleeping while reading.

Change-Id: Ib4e93b65f50cbad30d057ad7905617d00070c1a4
Reviewed-on: http://gerrit.openafs.org/3762
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>