Emit apex_info to target_files META/apex_info.pb

Test: mm -j
Bug: 172911822

Change-Id: I5a70b75dbe1cd546c66beaa8e4e3a63c3987461e
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index e8674b6..176e258 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -626,6 +626,10 @@
     elif filename in ["META/care_map.pb", "META/care_map.txt"]:
       pass
 
+    # Skip apex_info.pb because we sign/modify apexes
+    elif filename == "META/apex_info.pb":
+      pass
+
     # Updates system_other.avbpubkey in /product/etc/.
     elif filename in (
         "PRODUCT/etc/security/avb/system_other.avbpubkey",