scripts: Sleep for 200ms between symbol uploads
scripts: Sleep for 200ms between symbol uploads

To avoid looking like we're DoS'ing the symbol server, force a delay between
symbol uploads.  If this becomes a bottleneck for buildbots, this should be
modified to only upload symbol files that have changed, by checking against
the buildbot's previous debug.tgz.

BUG=chromium-os:26596
TEST=Manually ran upload_symbols against staging symbol server

Change-Id: Iecf11e26a70f0c44838fb13e2ebc6ebb78336c50
Reviewed-on: https://gerrit.chromium.org/gerrit/19566
Commit-Ready: Michael Krebs <d6638659c20694b0807ba6fa35ee0bac2e482e0f@chromium.org>
Reviewed-by: Michael Krebs <d6638659c20694b0807ba6fa35ee0bac2e482e0f@chromium.org>
Tested-by: Michael Krebs <d6638659c20694b0807ba6fa35ee0bac2e482e0f@chromium.org>

crawford/scripts,mjg59/scripts,nicescale/scripts,vmware/coreos-scripts,coreos/scripts,gtank/scripts,mischief/scripts,andrejro/coreos--scripts,mischief/scripts,endocode/scripts,crawford/scripts,marineam/coreos-scripts,endocode/scripts,glevand/coreos--scripts,sigma/coreos-scripts,zhang0137/scripts,sigma/coreos-scripts,andrejro/coreos--scripts,fivethreeo/scripts,fivethreeo/scripts,BugRoger/scripts,trnubo/scripts,gtank/scripts,mjg59/scripts,fivethreeo/scripts,bcwaldon/coreos-scripts,marineam/coreos-scripts,gtank/scripts,glevand/coreos--scripts,sigma/coreos-scripts,nicescale/scripts,smilart/scripts,crawford/scripts,endocode/scripts,marineam/coreos-scripts,zhang0137/scripts,BugRoger/scripts,mjg59/scripts,mischief/scripts,vmware/coreos-scripts,coreos/scripts,andrejro/coreos--scripts,nicescale/scripts,smilart/scripts,trnubo/scripts,bcwaldon/coreos-scripts,vmware/coreos-scripts,zhang0137/scripts,trnubo/scripts,BugRoger/scripts,smilart/scripts,bcwaldon/coreos-scripts