Fix pycrypto backend setting to work when multiple distros are specified in DEB_DIST

packaging/debian/control

@@ -3,7 +3,7 @@ Section: admin
 Priority: optional
 Standards-Version: 3.9.3
 Maintainer: Ansible, Inc. <info@ansible.com>
-Build-Depends: cdbs, debhelper (>= 5.0.0), asciidoc, python, dh-python | python-support, python-setuptools
+Build-Depends: cdbs, debhelper (>= 5.0.0), asciidoc, python, dh-python | python-support, python-setuptools, lsb-release
 Homepage: http://ansible.github.com/
 
 Package: ansible

packaging/debian/rules

@@ -6,7 +6,7 @@ DEB_PYTHON2_MODULE_PACKAGES=ansible
 include /usr/share/cdbs/1/rules/debhelper.mk
 include /usr/share/cdbs/1/class/python-distutils.mk
 
-ifeq ($(DEB_DIST), trusty)
+ifeq ($(shell lsb_release -cs), trusty)
   export ANSIBLE_CRYPTO_BACKEND = pycrypto
 endif