RTT bugfixes, part 5

* Stop destroying and re-creating the RTT pipes -- they have a complex
lifecycle on the other side of the pipe

Bug: 72648661
Bug: 72762206
Test: manual, with telecom testapp dialer over the network and Dialer
simulator

Change-Id: I4fd657e4c204386826fc6e7f9e529b673d16e001
Merged-In: I4fd657e4c204386826fc6e7f9e529b673d16e001