nss: remove obsolete signing-disabling patch

Obsolete since the Mac build uses NSS_USE_SYSTEM_SQLITE=1 now.

Change-Id: Ic02756c06a992d0f19849a4edf1e6305eafb8660
configure: NSS_MAJOR etc. unused since cffad630

Change-Id: I5182e538219e85e8c2b0ae615d02d9aaaff75ca5