Otapreopt: Fix after shared-library work

Commit b63d91fd2737680351876406277b6c759f4db33c broke the installd
to otapreopt connection. Fix this. Also refactor a bit to make an
inadvertant break harder.

Bug: 25612095
Change-Id: I8e7b944ecbd5457e4ac4d6ffffdb0468618cf65f
diff --git a/cmds/installd/installd_constants.h b/cmds/installd/installd_constants.h
index 8513695..823b8ee 100644
--- a/cmds/installd/installd_constants.h
+++ b/cmds/installd/installd_constants.h
@@ -21,6 +21,8 @@
 namespace android {
 namespace installd {
 
+constexpr size_t DEXOPT_PARAM_COUNT = 10U;
+
 /* elements combined with a valid package name to form paths */
 
 constexpr const char* PRIMARY_USER_PREFIX = "data/";