Merge branch 'readonly-p4-donut' into donut

diff --cc tools/releasetools/sign_target_files_apks
index 33fcf22,b632924..4889141
--- 1/tools/releasetools/sign_target_files_apks
--- 2/tools/releasetools/sign_target_files_apks
+++ b/tools/releasetools/sign_target_files_apks
@@@ -73,10 -67,10 +75,10 @@@ OPTIONS = common.OPTION
  
  OPTIONS.extra_apks = {}
  OPTIONS.key_map = {}
 -
 +OPTIONS.replace_ota_keys = False
  
  def GetApkCerts(tf_zip):
-   certmap = OPTIONS.extra_apks.copy()
+   certmap = {}
    for line in tf_zip.read("META/apkcerts.txt").split("\n"):
      line = line.strip()
      if not line: continue