Adapt the OS X build to use the OS X tar

As part of this, move release creation to a script to be called from
.travis.yml.  That makes it much easier to test outside of travis.
Reviewed-by: NRich Salz <rsalz@openssl.org>

.travis-create-release.sh

+#! /bin/sh
+
+# $1 is expected to be $TRAVIS_OS_NAME
+
+if [ "$1" == osx ]; then
+    make -f Makefile.org \
+	 DISTTARVARS="NAME=_srcdist TAR_COMMAND='\$\$(TAR) \$\$(TARFLAGS) -s \"|^|\$\$(NAME)/|\" -T \$\$(TARFILE).list -cvf -' TARFLAGS='-n' TARFILE=_srcdist.tar" SHELL='sh -vx' dist
+else
+    make -f Makefile.org DISTTARVARS='TARFILE=_srcdist.tar NAME=_srcdist' SHELL='sh -v' dist
+fi

.travis.yml

@@ -68,7 +68,7 @@ matrix:
           env: CONFIG_OPTS="--debug --strict-warnings"
 
 before_script:
-    - make -f Makefile.org TARFILE=_srcdist.tar NAME=_srcdist dist
+    - sh .travis-create-release.sh $TRAVIS_OS_NAME
     - tar -xvzf _srcdist.tar.gz
     - cd _srcdist
     - if [ "$CC" == i686-w64-mingw32-gcc ]; then