travis/ia32: Remove libc6.i386 dependency

Not needed anymore for CONFIG_COMPAT.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

scripts/build/Dockerfile.x86_64.hdr

 FROM ubuntu:trusty
 
 RUN apt-get update -qq && apt-get install -qq \
-                gcc-multilib \
-                libc6-dev-i386
+                gcc-multilib

scripts/travis/travis-tests

@@ -3,7 +3,7 @@ set -x -e
 
 TRAVIS_PKGS="protobuf-c-compiler libprotobuf-c0-dev libaio-dev
 		libprotobuf-dev protobuf-compiler python-ipaddr libcap-dev
-		libnl-3-dev gcc-multilib libc6-dev-i386 gdb bash python-protobuf
+		libnl-3-dev gcc-multilib gdb bash python-protobuf
 		libnet-dev util-linux asciidoc xmlto"
 
 travis_prep () {