acrobatreaderdc does not need to be in versioned sub-dir

Having the mst in a dir involving %mainversion% will lead to a maintenance
headache when doing upgrades. I've been using the same mst without problems
for a few years' worth of DC versions.

packages/acrobatreaderdc.xml

@@ -10,7 +10,7 @@
   <check type="uninstall" condition="versiongreaterorequal" path="Adobe Acrobat Reader DC" value="%version%" />
 
   <!-- patches are cumulative; we only need to apply the latest one -->
-  <install cmd='msiexec /qn /i "%WPKGSOFTWARE%\Adobe\AcrobatReaderDC\%mainversion%\AcroRead.msi" /l* c:\netinst\logs\ReaderDC.log TRANSFORMS="%WPKGSHAREBASE%\%WPKGINSTITUTION%-config\Adobe\AcrobatReaderDC\%mainversion%\%WPKGINSTITUTION%.mst"'>
+  <install cmd='msiexec /qn /i "%WPKGSOFTWARE%\Adobe\AcrobatReaderDC\%mainversion%\AcroRead.msi" /l* c:\netinst\logs\ReaderDC.log TRANSFORMS="%WPKGSHAREBASE%\%WPKGINSTITUTION%-config\Adobe\AcrobatReaderDC\%WPKGINSTITUTION%.mst"'>
     <exit code="0" />
     <exit code="3010" reboot="false" />
   </install>