Do not initialize SSLSocketFactory too early

During Zygote initialization, the class may be preloaded. However we do
not want the default instances of SSLSocketFactory initialized, so move
those into a holder class so they are only initialized when used.

Bug: 9984058
Change-Id: Icf91f4fb60b7e4e5e9fbb22def01073dc1663128
Merge tag 'tags/android-4.4_r1' into kitkat-staging

Android 4.4 Release 1.0