Upgrade libcups to v2.3.1

Local changes:
1. Makes _cupsSetHTTPError visible because it is used in
BuiltInPrintService.
2. Adds config.h and cups/tls-boringssl.c.

Bug: 168903843
Test: Build the code, flash the device and run fuzzer
Exempt-From-Owner-Approval: upgrade
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c56dfec131379d6ad0967503a3dab26e1529d3dd)
Merged-In: Iabc33a8248ee1441333ab0e0ace8cf1965a5b866
Change-Id: Iabc33a8248ee1441333ab0e0ace8cf1965a5b866
diff --git a/templates/ru/printer-added.tmpl b/templates/ru/printer-added.tmpl
new file mode 100644
index 0000000..c2b3df2
--- /dev/null
+++ b/templates/ru/printer-added.tmpl
@@ -0,0 +1,3 @@
+<H2 CLASS="title">Добавить принтер</H2>
+
+<P>Принтер <A HREF="/printers/{printer_name}">{printer_name}</A> успешно добавлен.