cros_install_debug_syms: use portage's boto config

All calls to google storage should use the same boto config file used by
portage.

BUG=chrome-os-partner:34702,chromium:443380
TEST=move /home/$USER/.boto. `./build_packages --board=gizmo` works

CQ-DEPEND=CL:236413

Change-Id: I71551a46f3d20ef7025eef001dead7a6b7d54b55
Reviewed-on: https://chromium-review.googlesource.com/236368
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_install_debug_syms.py b/scripts/cros_install_debug_syms.py
index a913484..ff11252 100644
--- a/scripts/cros_install_debug_syms.py
+++ b/scripts/cros_install_debug_syms.py
@@ -280,6 +280,10 @@
   if options.cachebinhost:
     binhost_cache = cache.DiskCache(cache_dir)
 
+  boto_file = vartree.settings['BOTO_CONFIG']
+  if boto_file:
+    os.environ['BOTO_CONFIG'] = boto_file
+
   gs_context = gs.GSContext()
   symbols_mapping = RemoteSymbols(vartree, binhost_cache)