FBE for Pixel 2

Includes various minor fixes for building in Android 8 trees with r23+ tag

Update FBE extended header in libtar to version 2 and include the entire
ext4_encryption_policy structure now after translating the policy.

See this post for more details:
https://plus.google.com/u/1/+DeesTroy/posts/i33ygUi7tiu

Change-Id: I2af981e51f459b17fcd895fb8c2d3f6c8200e24b
diff --git a/partitionmanager.cpp b/partitionmanager.cpp
index 0486c7a..54ce691 100644
--- a/partitionmanager.cpp
+++ b/partitionmanager.cpp
@@ -91,9 +91,11 @@
 	stop_backup.set_value(0);
 #ifdef AB_OTA_UPDATER
 	char slot_suffix[PROPERTY_VALUE_MAX];
-	property_get("ro.boot.slot_suffix", slot_suffix, "_a");
+	property_get("ro.boot.slot_suffix", slot_suffix, "error");
+	if (strcmp(slot_suffix, "error") == 0)
+		property_get("ro.boot.slot", slot_suffix, "error");
 	Active_Slot_Display = "";
-	if (strcmp(slot_suffix, "_a") == 0)
+	if (strcmp(slot_suffix, "_a") == 0 || strcmp(slot_suffix, "a") == 0)
 		Set_Active_Slot("A");
 	else
 		Set_Active_Slot("B");