Revert "Restore parent mount namespace before executing a child process"

This reverts commit a0ef21262f4d5652bfb65cfacaec01d89c475a93. This
doesn't work in 'nix run' and nix-shell because setns() fails in
multithreaded programs, and Boehm GC mark threads are uncancellable.

Fixes #2646.

1 files changed, 0 insertions, 2 deletions

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 5b4e7ca4ca99..485fdd691932 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -366,8 +366,6 @@ void LocalStore::makeStoreWritable()
         throw SysError("getting info about the Nix store mount point");
 
     if (stat.f_flag & ST_RDONLY) {
-        saveMountNamespace();
-
         if (unshare(CLONE_NEWNS) == -1)
             throw SysError("setting up a private mount namespace");