tests: just use the sha1sum implemented in Ruby

The output of SHA1 command-line tools is too unstable and
I'm more comfortable with Ruby 1.9 encoding support than
I was in 2009.

Jeremy Evans noted the output of "openssl sha1" has
changed since I last used it.

t/bin/sha1sum.rb

@@ -1,12 +1,6 @@
 #!/usr/bin/env ruby
 # -*- encoding: binary -*-
-
-# Reads from stdin and outputs the SHA1 hex digest of the input this is
-# ONLY used as a last resort, our test code will try to use sha1sum(1),
-# openssl(1), or gsha1sum(1) before falling back to using this.  We try
-# all options first because we have a strong and healthy distrust of our
-# Ruby abilities in general, and *especially* when it comes to
-# understanding (and trusting the implementation of) Ruby 1.9 encoding.
+# Reads from stdin and outputs the SHA1 hex digest of the input
 
 require 'digest/sha1'
 $stdout.sync = $stderr.sync = true

t/test-lib.sh

@@ -100,11 +100,5 @@ unicorn_wait_start () {
 }
 
 rsha1 () {
-	_cmd="$(which sha1sum 2>/dev/null || :)"
-	test -n "$_cmd" || _cmd="$(which openssl 2>/dev/null || :) sha1"
-	test "$_cmd" != " sha1" || _cmd="$(which gsha1sum 2>/dev/null || :)"
-
-	# last resort, see comments in sha1sum.rb for reasoning
-	test -n "$_cmd" || _cmd=sha1sum.rb
-	expr "$($_cmd)" : '\([a-f0-9]\{40\}\)'
+	sha1sum.rb
 }