Fixed occasional off-by-one

Looking at the current commit is not a good idea. geekosaur++

README.md

@@ -13,7 +13,7 @@ Currently ``AlexDaniel`` is maintaining it.
 
 ```
 <moritz> bisect: try { NaN.Rat == NaN; exit 0 }; exit 1
-<bisectable> moritz: (2016-05-02) https://github.com/rakudo/rakudo/commit/949a7c7
+<bisectable> moritz: (2016-05-02) https://github.com/rakudo/rakudo/commit/e2f1fa7
 ```
 
 ```
@@ -36,4 +36,4 @@ Run ``new-commits`` script periodically to process new commits.
 Basically, that's it.
 
 Some of these scripts are sensitive to the current working directory.
-Use with care.
+Use with care.

bot.pl

@@ -66,7 +66,7 @@ sub said {
     system('git', 'bisect', 'good', $good);
     system('git', 'bisect', 'bad',  $bad);
     system('git', 'bisect', 'run',  $commit_tester, $builds, $filename);
-    my $result = `git log -n 1 --date=short --pretty='(%cd) $link/%h'`;
+    my $result = `git show --quiet --date=short --pretty='(%cd) $link/%h' bisect/bad`;
     chdir($oldDir);
 
     return "$message->{who}: $result";