removing an unused html file from the build, dispensation per 122806, r=cotter

extensions/help/resources/jar.mn

@@ -41,7 +41,6 @@ en-US.jar:
         locale/en-US/help/using_priv_help.html          (locale/en-US/using_priv_help.html)
         locale/en-US/help/using_certs_help.html         (locale/en-US/using_certs_help.html)
         locale/en-US/help/validation_help.html          (locale/en-US/validation_help.html)
-        locale/en-US/help/context_help.html             (locale/en-US/context_help.html)
         locale/en-US/help/content_style.css             (locale/en-US/content_style.css)
         locale/en-US/help/help.dtd                      (locale/en-US/help.dtd)
         locale/en-US/help/helpMenuOverlay.dtd           (locale/en-US/helpMenuOverlay.dtd)