fix packaging after README was turned into mark-up

Author: vladak

platform/solaris/pkgdef/prototype

@@ -52,7 +52,7 @@ f none usr/opengrok/bin/Groups=tools/Groups 0555 bin bin
 f none usr/opengrok/bin/ConfigMerge=tools/ConfigMerge 0555 bin bin
 f none usr/opengrok/bin/Messages=tools/Messages 0555 bin bin
 f none usr/opengrok/doc/logging.properties=logging.properties 0444 root sys
-f none usr/opengrok/doc/README.txt=README.txt 0444 root sys
+f none usr/opengrok/doc/README.md=README.md 0444 root sys
 f none usr/opengrok/doc/CHANGES.txt=CHANGES.txt 0444 root sys
 f none usr/opengrok/doc/LICENSE.txt=LICENSE.txt 0444 root sys
 f none usr/opengrok/doc/NOTICE.txt=NOTICE.txt 0444 root sys