Correct a backport inconsistency in bind-9.11-rt46047.patch
The patch seems to have been generated from a more recent bind
tree in which `ns_g_lctx` was renamed `named_g_lctx`. So the
patch uses the `named_g_lctx` name, but the rest of server.c
in bind-9.11 still uses the name `ns_g_lctx`, so if you compile
with --disable-crypto-rand, the build actually fails with an
undeclared name error.