Reboot and retry on I/O errors

When I/O error happens, reboot and retry installation two times
before we abort this OTA update.

Bug: 25633753
Change-Id: Iba6d4203a343a725aa625a41d237606980d62f69
diff --git a/install.h b/install.h
index f92f061..fd08e3c 100644
--- a/install.h
+++ b/install.h
@@ -23,7 +23,8 @@
 extern "C" {
 #endif
 
-enum { INSTALL_SUCCESS, INSTALL_ERROR, INSTALL_CORRUPT, INSTALL_NONE, INSTALL_SKIPPED };
+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.