build_packages: don't install debug symbols by default

Debug symbols should only be installed when required or when explicitly
asked for (--withdebugsymbols).

BUG=chromium:455392
TEST=manual: build_packages does not install debug symbols by default.
TEST=trybots.

Change-Id: I04c2e02510a6b70e5992ae0a4d67983be9fa7289
Reviewed-on: https://chromium-review.googlesource.com/248110
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Trybot-Ready: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/build_packages b/build_packages
index 780f0c0..ebc821a 100755
--- a/build_packages
+++ b/build_packages
@@ -28,7 +28,7 @@
   "Don't build anything, instead only fetch what is needed."
 DEFINE_boolean unpackonly "${FLAGS_FALSE}" \
   "Don't build anything; instead only fetch and unpack what is needed."
-DEFINE_boolean withdebugsymbols "${FLAGS_TRUE}" \
+DEFINE_boolean withdebugsymbols "${FLAGS_FALSE}" \
   "Install the debug symbols for all packages"
 
 # The --board_root flag specifies the environment variables ROOT and PKGDIR.