OSL-2.0: Fix "Licensev." -> "License v."

The typo came in with the license in 0162ea9 (Automated, 2016-03-30,
#180).

Also add an optional "The " to match the archived original:

  $ curl -s https://web.archive.org/web/20041020171434/http://www.rosenlaw.com/osl2.0.html | grep 'Open Software License' | head -n2
  <!-- End Wayback Rewrite JS Include --><h1>The Open Software License<br/> v. 2.0</h1>
  <p>This Open Software License (the "License") ...

Author: wking

src/OSL-2.0.xml

@@ -6,7 +6,7 @@
       </crossRefs>
       <standardLicenseHeader>Licensed under the Open Software License version 2.0</standardLicenseHeader>
       <titleText>
-         <p>Open Software Licensev. 2.0</p>
+         <p><optional>The </optional>Open Software License v. 2.0</p>
       </titleText>
 
       <p>This Open Software License (the "License") applies to any original work of authorship (the