add --ssh_verbosity flag to run_remote_tests

This CL adds a --ssh_verbosity flag to run_remote tests, that gets
passed through to autoserv. Values other than 0 might be useful for
debugging ssh issues.

CQ-DEPEND=CL:If705c03f9d9d70de89642f42904e2e9fdc40bf61
BUG=chromium:271621
TEST=Ran run_remote_tests with the new argument, ensured that it was
being passed along to autoserv. Note: using the maximum ssh verbosity
level of 3 frequently caused autoserv to hang. I will file a separate
issue about that once this is landed.

Change-Id: Ia3ecb3eaa4bf3054f236fa03bb347b60622767ca
Reviewed-on: https://gerrit.chromium.org/gerrit/65635
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
diff --git a/run_remote_tests.sh b/run_remote_tests.sh
index 07f37c8..c5e00a0 100755
--- a/run_remote_tests.sh
+++ b/run_remote_tests.sh
@@ -39,6 +39,8 @@
     "Proceed with testing even if remote is offline; useful when using servo"
 DEFINE_boolean fast ${FLAGS_FALSE} \
     "Drop expensive autoserv features not needed for desk use"
+DEFINE_string ssh_verbosity "0" \
+    "ssh_verbosity level passed through to autserv, between 0 and 3 inclusive"
 
 # The prefix to look for in an argument that determines we're talking about a
 # new-style suite.
@@ -675,7 +677,8 @@
     local autoserv_args="-m ${FLAGS_remote} --ssh-port ${FLAGS_ssh_port} \
         ${image} ${option} ${control_file} -r ${results_dir} ${verbose} \
         ${FLAGS_label:+ -l $FLAGS_label} \
-        --test-retry=${test_retry_value} ${fast_flags}"
+        --test-retry=${test_retry_value} ${fast_flags} \
+        --ssh_verbosity ${FLAGS_ssh_verbosity}"
 
     sudo chmod a+w ./server/{tests,site_tests}