thirdparty: fix to protobuf bump
thirdparty: fix to protobuf bump

Commit 57de48d bumped protobuf to 3.4.1 but didn't remove the call to
delete_if_wrong_patchlevel, which meant that every time
download-thirdparty.sh was run, it'd redownload and reextract protobuf.

Rather than remove delete_if_wrong_patchlevel, this patch sets protobuf to
use patchlevel 0. That way, download-thirdparty.sh will rebuild protobuf
when switching between different git branches with differing protobuf
patchlevels. If we had removed the patchlevel altogether, it wouldn't be
smart enough to recognize a change and rebuild when switching back to "now".

Change-Id: I3d1d05b60051a355a177dd2807ac56debaf1b7a0
Reviewed-on: http://gerrit.cloudera.org:8080/8115
Tested-by: Kudu Jenkins
Reviewed-by: David Ribeiro Alves <dbbafdb4f25eb0c1ff3facf0e5f2f27705055af1@gmail.com>

helifu/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,andrwng/kudu,cloudera/kudu,EvilMcJerkface/kudu,cloudera/kudu,cloudera/kudu,helifu/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,cloudera/kudu,InspurUSA/kudu,andrwng/kudu,InspurUSA/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,InspurUSA/kudu,helifu/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,InspurUSA/kudu,andrwng/kudu,helifu/kudu,andrwng/kudu,helifu/kudu,andrwng/kudu,andrwng/kudu,cloudera/kudu