PR10595 Work around uprobe2 causing selinux failures for kernel 2.6.28+.

PR10595 Work around uprobe2 causing selinux failures for kernel 2.6.28+.

We allocate a "fake" unlinked shmem file because anonymous
memory might not be granted execute permission when the selinux
security hooks have their way. Only do this for 2.6.28 or higher
since shmem_file_setup() isn't exported before that.

* runtime/uprobes2/uprobes.c (uprobe_setup_ssol_vma): Use shmem_file_setup
  to setup the ssol vma area when using 2.6.28+.