Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=57344
Provide sha1 checksum files for Tomcat downloads.
Exclude stray *.asc file from apache-tomcat-*-embed.tar.gz archive.

Backport of r1645360 from tomcat/tc8.0.x/trunk
(r1645357 from tomcat/trunk).

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1645361 13f79535-47bb-0310-9956-ffa450edef68