releasetools: Skip copying split super images while signing.

Bug: 122608028
Test: Run sign_target_files_apks.py on a target-files zip that has split
      super images (e.g. OTA/super_system.img).
Change-Id: Iaf7263790961a897ea3f339f5af6b18cf253b946

tools/releasetools/sign_target_files_apks.py

@@ -309,6 +309,10 @@ def ProcessTargetFiles(input_tf_zip, output_tf_zip, misc_info,
     if filename.startswith("IMAGES/"):
       continue
 
+    # Skip split super images, which will be re-generated during signing.
+    if filename.startswith("OTA/") and filename.endswith(".img"):
+      continue
+
     data = input_tf_zip.read(filename)
     out_info = copy.copy(info)
     (is_apk, is_compressed, should_be_skipped) = GetApkFileInfo(