efi_loader: fix EFI_FILE_PROTOCOL.GetInfo()

We check the existence of files with fs_exist(). This function calls
fs_close(). If we do not set the active block device again fs_opendir()
fails and we do not set the flag EFI_FILE_DIRECTORY. Due to this error the
`cd` command in the EFI shell fails.

So let's add the missing set_blk_dev(fh) call.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c
index 9d709a8..4b44222 100644
--- a/lib/efi_loader/efi_file.c
+++ b/lib/efi_loader/efi_file.c
@@ -200,6 +200,10 @@
 			     fs_exists(fh->path)))
 			goto error;
 
+		/* fs_exists() calls fs_close(), so open file system again */
+		if (set_blk_dev(fh))
+			goto error;
+
 		/* figure out if file is a directory: */
 		fh->isdir = is_dir(fh);
 	} else {