Add /data/apex to directories that don't need to be encrypted.

There's no user data there, just code.

Bug: 112455435
Test: Using an APEX with Direct I/O in /data/apex works again
Change-Id: I5e5557445ea5d638d2dfc4db7d782ee2da207bc1
diff --git a/ext4_utils/ext4_crypt_init_extensions.cpp b/ext4_utils/ext4_crypt_init_extensions.cpp
index c067bb9..728949e 100644
--- a/ext4_utils/ext4_crypt_init_extensions.cpp
+++ b/ext4_utils/ext4_crypt_init_extensions.cpp
@@ -88,6 +88,7 @@
         "vendor_ce", "vendor_de",
         "media",
         "data", "user", "user_de",
+        "apex",
     };
     std::string prefix = "/data/";
     for (auto d: directories_to_exclude) {