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/install.h b/install.h
index 7f66a51..1ec01e8 100644
--- a/install.h
+++ b/install.h
@@ -20,10 +20,9 @@
 #include <string>
 #include <ziparchive/zip_archive.h>
 
-#include "common.h"
-
 enum { INSTALL_SUCCESS, INSTALL_ERROR, INSTALL_CORRUPT, INSTALL_NONE, INSTALL_SKIPPED,
         INSTALL_RETRY };
+
 // Install the package specified by root_path.  If INSTALL_SUCCESS is
 // returned and *wipe_cache is true on exit, caller should wipe the
 // cache partition.