Revert "Revert "Some cleanups to recovery.""

This reverts commit 8584fcf677dd45b30121bd0490b06297e6be1871.

This CL re-lands commit c0319b60f56d445c2d1c74f551e01f069b028fe6.
The "stage" and "reason" variables are now declared as global by
dropping the static qualifier, because they may be used by vendor
recovery libraries.

Test: lunch aosp_angler-userdebug; mmma bootable/recovery
Test: lunch aosp_dragon-userdebug; mmma bootable/recovery

Change-Id: I252c346f450079478cff22bbff01590b8ab2e2b3
diff --git a/roots.h b/roots.h
index a14b7d9..542f03b 100644
--- a/roots.h
+++ b/roots.h
@@ -17,7 +17,7 @@
-#include "common.h"
+typedef struct fstab_rec Volume;
 // Load and parse volume data from /etc/recovery.fstab.
 void load_volume_table();