Use -I/usr/include/libchrome

This CL stops using /usr/include/base-${libbase_ver}, which is currently
a symlink pointing to /usr/include/libchrome.

This is part of effort to remove basever in libchrome-related file
names.

BUG=chromium:1094927
TEST=CQ

Change-Id: I6dea1bce1b1d9b42d387b89c8abc980eca69faf3
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/external/libchrome/+/2596698
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Qijiang Fan <fqj@google.com>
Tested-by: Qijiang Fan <fqj@google.com>