Add --service-client option to migration script

We are migrating service clients to tempeset-lib, but we needed to
update many places by hands even if using the migration script.
There is a pattern of update, so this patch adds a new option
--service-client for updating them automatically.
We can use it like:

 $ tools/migrate_from_tempest.sh -u ../tempest -s \
   tempest/services/compute/json/availability_zone_client.py \
   tempest/tests/services/compute/test_availability_zone_client.py \
   tempest/api_schema/response/compute/v2_1/availability_zone.py

Partially implements blueprint migrate-service-clients-to-tempest-lib

Change-Id: Iab832501725cedd5c5fcc65d760ce8a9794223ac

tools/migrate_from_tempest.sh

@@ -23,12 +23,14 @@ function usage {
 set -e
 
 output_dir=""
+service_client=0
 
 while [ $# -gt 0 ]; do
     case "$1" in
         -h|--help) usage; exit;;
         -o|--output_dir) output_dir="$2"; shift;;
         -u|--tempest_git_url) tempest_git_url="$2"; shift;;
+        -s|--service_client) service_client=1;;
         *) files="$files $1";;
     esac
     shift
@@ -64,9 +66,28 @@ for file in $files; do
         dirname="$output_dir"
     else
         dirname=`echo $dirname | sed s@tempest\/@tempest_lib/\@`
+        if [ $service_client -eq 1 ]; then
+            # Remove /json path because tempest-lib supports JSON only without XML
+            dirname=`echo $dirname | sed s@\/json@@`
+        fi
     fi
     dest_file="$dirname/$filename"
     cp -r "$tmpdir/$file" "$dest_file"
+
+    if [ $service_client -eq 1 ]; then
+        # service_client module is not necessary in tempest-lib because rest_client can be used instead
+        sed -i s/"from tempest.common import service_client"/"from tempest_lib.common import rest_client"/ $dest_file
+        sed -i s/"service_client.ServiceClient"/"rest_client.RestClient"/  $dest_file
+        sed -i s/"service_client.ResponseBody"/"rest_client.ResponseBody"/ $dest_file
+        sed -i s/"from tempest\."/"from tempest_lib\."/ $dest_file
+
+        # Replace mocked path in unit tests
+        sed -i s/"tempest.common.rest_client"/"tempest_lib.common.rest_client"/ $dest_file
+
+        # Remove ".json" from import line
+        sed -i -e "s/^\(from tempest_lib\.services\..*\)\.json\(.*\)/\1\2/" $dest_file
+    fi
+
     git add "$dest_file"
     if [[ -z "$file_list" ]]; then
         file_list="$filename"