[extended tests] Enable krb5 tests in Travis

Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2022)

.gitmodules

@@ -5,3 +5,7 @@
 [submodule "pyca.cryptography"]
 	path = pyca-cryptography
 	url = https://github.com/pyca/cryptography.git
+
+[submodule "krb5"]
+	path = krb5
+	url = https://github.com/krb5/krb5

.travis.yml

@@ -196,6 +196,9 @@ script:
               sudo apt-get -yq --no-install-suggests --no-install-recommends --force-yes install wine;
               export EXE_SHELL="wine" WINEPREFIX=`pwd`;
           fi;
+          if [ -e krb5/src ]; then
+              sudo apt-get -yq install bison dejagnu gettext keyutils ldap-utils libldap2-dev libkeyutils-dev python-cjson python-paste python-pyrad slapd tcl-dev tcsh;
+          fi;
           HARNESS_VERBOSE=yes BORING_RUNNER_DIR=$top/boringssl/ssl/test/runner make test;
       else
           $make build_tests;

krb5 @ b9ad6c49

+Subproject commit b9ad6c49505c96a088326b62a52568e3484f2168