forgot to add the help screen for new cvs.exe path configuration option.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1811 71c3de6d-444a-0410-be80-ed276b4c234a

war/resources/help/_cvs/cvsexe.html

+<div>
+  If your <tt>cvs</tt> binary exists outside your <tt>PATH</tt>, specify the absolute
+  path to the cvs executable. If you just specify "cvs", it will find cvs from <tt>PATH</tt>.
+</div>
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