Remove EXPAND/STRINGIFY macros.

They are error-prone by putting anything into a string (e.g.
EXPAND(RECOVERY_API_VERSION) would become "RECOVER_API_VERSION" if we
forgot to pass -DRECOVERY_API_VERSION=3).

RECOVERY_API_VERSION is the only user (in bootable/recovery) that gets
stringified. Assign it to a typed var and sanity check the value.

Don't see other reference to the macros from device-specific recovery
directories (they can still define that locally if really needed).

Test: recovery_component_test
Test: Sideload an OTA on angler and marlin respectively.
Change-Id: I358bbdf8f0a99db5ce4c7bc2fdcafe8013501b64
diff --git a/recovery.cpp b/recovery.cpp
index 944c240..6dd9858 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -1501,7 +1501,7 @@
     property_list(print_property, NULL);
     printf("\n");
 
-    ui->Print("Supported API: %d\n", RECOVERY_API_VERSION);
+    ui->Print("Supported API: %d\n", kRecoveryApiVersion);
 
     int status = INSTALL_SUCCESS;