allow recovery packages to wipe cache

updater now has a function "wipe_cache();" which causes recovery to
wipe the cache partition after the successful installation of the
package.  Move log copying around a bit so logs and the last_install
flag file are copied to cache after it's wiped.

Bug: 5314244
Change-Id: Id35a9eb6dcd626c8f3a3a0076074f462ed3d44bd
diff --git a/install.h b/install.h
index a7ebc09..5ebe160 100644
--- a/install.h
+++ b/install.h
@@ -20,6 +20,10 @@
 #include "common.h"
 
 enum { INSTALL_SUCCESS, INSTALL_ERROR, INSTALL_CORRUPT };
-int install_package(const char *root_path);
+// 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.
+int install_package(const char *root_path, int* wipe_cache,
+                    const char* install_file);
 
 #endif  // RECOVERY_INSTALL_H_