Telemetry instances should now be created with rtb-n1-standard-8-d

BUG=skia:

Review URL: https://codereview.chromium.org/199843006
diff --git a/compute_engine_scripts/telemetry/telemetry_master_scripts/vm_recover_slaves_from_crashes.sh b/compute_engine_scripts/telemetry/telemetry_master_scripts/vm_recover_slaves_from_crashes.sh
index a9a6cd1..5127ec4 100644
--- a/compute_engine_scripts/telemetry/telemetry_master_scripts/vm_recover_slaves_from_crashes.sh
+++ b/compute_engine_scripts/telemetry/telemetry_master_scripts/vm_recover_slaves_from_crashes.sh
@@ -35,7 +35,7 @@
       --service_account_scopes="https://www.googleapis.com/auth/devstorage.full_control" \
       --network=skia \
       --image=skiatelemetry-3-0-v20131101 \
-      --machine_type=n1-standard-4-d \
+      --machine_type=rtb-n1-standard-8-d \
       --external_ip_address=108.170.222.${SLAVE_NUM} \
       --nopersistent_boot_disk \
       --service_version=v1beta16
diff --git a/compute_engine_scripts/telemetry/vm_create_cluster.sh b/compute_engine_scripts/telemetry/vm_create_cluster.sh
index 5f09bbe..bd32b29 100755
--- a/compute_engine_scripts/telemetry/vm_create_cluster.sh
+++ b/compute_engine_scripts/telemetry/vm_create_cluster.sh
@@ -26,7 +26,7 @@
   --service_account_scopes="$SCOPES" \
   --network=skia \
   --image=skiatelemetry-3-0-v20131101 \
-  --machine_type=n1-standard-8-d \
+  --machine_type=rtb-n1-standard-8-d \
   --nopersistent_boot_disk \
   --service_version=v1beta16
 
@@ -41,7 +41,7 @@
     --service_account_scopes="$SCOPES" \
     --network=skia \
     --image=skiatelemetry-3-0-v20131101 \
-    --machine_type=n1-standard-8-d \
+    --machine_type=rtb-n1-standard-8-d \
     --external_ip_address=${FREE_IP_LIST[$FREE_IP_INDEX]} \
     --nopersistent_boot_disk \
     --service_version=v1beta16
diff --git a/compute_engine_scripts/telemetry/vm_create_setup_recreateskps_bot.sh b/compute_engine_scripts/telemetry/vm_create_setup_recreateskps_bot.sh
index eaf7a3f..4f8c366 100755
--- a/compute_engine_scripts/telemetry/vm_create_setup_recreateskps_bot.sh
+++ b/compute_engine_scripts/telemetry/vm_create_setup_recreateskps_bot.sh
@@ -25,7 +25,7 @@
   --service_account_scopes="$SCOPES" \
   --network=skia \
   --image=skiatelemetry-3-0-v20131101 \
-  --machine_type=n1-standard-8-d \
+  --machine_type=rtb-n1-standard-8-d \
   --nopersistent_boot_disk \
   --service_version=v1beta16