autotest: Run wifi_perf suite for branches >=R34

We'll need to port the suite back to earlier releases if we want to
run performance tests against those branches.

BUG=chromium:336118
TEST=None

Change-Id: I46d79c85d01f625aad25964a4b7fab91127e7b36
Reviewed-on: https://chromium-review.googlesource.com/183175
Reviewed-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
Tested-by: Christopher Wiley <wiley@chromium.org>
diff --git a/suite_scheduler.ini b/suite_scheduler.ini
index 9941421..fbf336b 100644
--- a/suite_scheduler.ini
+++ b/suite_scheduler.ini
@@ -257,7 +257,7 @@
 [WiFi_Perf]
 run_on: nightly
 suite: wifi_perf
-branch_specs: >= R29
+branch_specs: >=R34
 pool: wificell
 
 [WiMAX]