add -E option in sudo to preserve env variable for pyenv

Bug: n/a
Test: n/a
Change-Id: I395c131e824105f248cc772b63f79e85cb2f51f5
diff --git a/build/debian/kokoro/gcp_ubuntu_docker/build.sh b/build/debian/kokoro/gcp_ubuntu_docker/build.sh
index 88ce921..c5745d0 100644
--- a/build/debian/kokoro/gcp_ubuntu_docker/build.sh
+++ b/build/debian/kokoro/gcp_ubuntu_docker/build.sh
@@ -10,4 +10,4 @@
 python --version
 
 sudo losetup -D
-sudo ./build.sh
+sudo -E ./build.sh