host: start_devserver: Remove exporting install mask

Remove exporting DEFAULT_INSTALL_MASK.

BUG=b:241001394
TEST=None

Cq-Depend: chromium:3803792
Change-Id: I9f0b79fd1a5149b1e1f0ea7bca8625845fe59345
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/3807650
Tested-by: Ram Chandrasekar <rchandrasekar@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Ram Chandrasekar <rchandrasekar@google.com>
diff --git a/host/start_devserver b/host/start_devserver
index 06fa7fb..b3f0819 100755
--- a/host/start_devserver
+++ b/host/start_devserver
@@ -3,7 +3,5 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-export DEFAULT_INSTALL_MASK
-
 # Exec the devserver, replacing this shell process.
 exec /usr/lib/devserver/devserver.py "$@"