Use metadata_key_dir instead of metadata_encryption

Eric pointed that metadata_key_dir is what specifies that metadata encryption
is enabled, whereas metadata_encryption is the metadata encryption options,
which don't have to be specified if the default options are sufficient.

Bug: 208161227
Fixes: 80a1d8e34116 ("Avoid to format raw disk if metadata encryption is enabled")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Change-Id: I390450ba49c528b1f465c247d32174d36c7937a2
diff --git a/recovery_utils/roots.cpp b/recovery_utils/roots.cpp
index d761e75..7fe385b 100644
--- a/recovery_utils/roots.cpp
+++ b/recovery_utils/roots.cpp
@@ -182,7 +182,7 @@
   // to get any failure in the process. In order to avoid it, let's simply wipe
   // the raw disk if we don't reserve any space, which behaves exactly same as booting
   // after "fastboot -w".
-  if (!v->metadata_encryption.empty() && length == 0) {
+  if (!v->metadata_key_dir.empty() && length == 0) {
     android::base::unique_fd fd(open(v->blk_device.c_str(), O_RDWR));
     if (fd == -1) {
       PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;