Document a dependency on Ubuntu 14.04 with LDAP for ART testing.

Reported by ARM.

On 64-bit Ubuntu 14.04 hosts using LDAP, running ART's
32-bit host Checker tests requires the package
libnss-sss:i386.

Detailed explanation from ARM:

  "The native method libcore.io.Posix.getpwuid() invokes the
  getpwuid_r() function from the standard library, which on
  Ubuntu 14.04 tries to dlopen() libnsss-sss if the machine
  is configured to use LDAP for user authentication (a common
  setup in enterprise environments). However, by default
  Ubuntu installs only the 64-bit version of the library (if
  the distribution architecture is also 64-bit), since that
  is all that's needed to let users log in, so the call to
  getpwuid_r() fails."

Bug: 30350792
Change-Id: Ifb38666f97494644209184fb4e6981c008b467cb
1 file changed