fixup! Allow ota_from_target_file to work entirely on directories

The following log message would always be shown:
WARNING : Cannot find care map file in target_file package

Break out of the care map copying loop as soon a file has been
copied. This ensures that else statement is only executed if no
care map file exists.

Test: Manual. Run ota_from_target_files with target-zip with and
    without care map files.
Change-Id: Ia196aa182ed81f21424317a7005f5634866b4b99
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index afbe81a..4c0d391 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1063,6 +1063,8 @@
       # ZIP_STORED.
       common.ZipWriteStr(output_zip, care_map_name, care_map_data,
                          compress_type=zipfile.ZIP_STORED)
+      # break here to avoid going into else when care map has been handled
+      break
     else:
       logger.warning("Cannot find care map file in target_file package")