Fix data_files_to_preserve.txt and update.sh

scripts/update.sh

 #!/bin/bash
 # Copyright (c) 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This is used to prepare for a major version update of ICU (e.g. from
 # 54.1 to 56.1). Running this script is step 1 in README.chromium.
 
 if [ $# -lt 1 ];
 then
   echo "Usage: "$0" version (e.g. '56-1')" >&2
   exit 1
 fi
 
 version="$1"
 repoprefix="http://source.icu-project.org/repos/icu/icu/tags/release-"
-repo="${repoprefix}${version}"
+repo="${repoprefix}${version}/icu4c"
 treeroot="$(dirname "$0")/.."
 
 # Check if the repo for $version is available.
 svn ls "${repo}" > /dev/null 2>&1  || \
     { echo "${repo} does not exist." >&2; exit 2; }
 
 echo "Cleaning up source/ ..."
 for file in source LICENSE license.html readme.html APIChangeReport.html
 do
   rm -rf "${treeroot}/${file}"
@@ skipping 24 matching lines @@
 echo "Patching configure to work without source/{layoutex,test}  ..."
 sed -i.orig -e '/^ac_config_files=/ s:\ layoutex/Makefile::g' \
   -e '/^ac_config_files=/ s: test/.* samples/M: samples/M:' \
   "${treeroot}/source/configure"
 rm -f "${treeroot}/source/configure.orig"
 
 # TODO(jshin): Automatically update BUILD.gn and icu.gypi with the updated
 # list of source files.
 
 echo "Done"