archivers/snappy-java: Remove duplicate in distinfo

A bug in Makefile caused duplicate entries in distinfo after make makesum.

While here remove GH_TAGNAME - it have default value.

PR: 288452
Approved by: Angelo Polo <language.devel@gmail.com> (maintainer, implicit)
Fixes: 88dd12d5f35c (Update 1.1.10.5 => 1.1.10.8)
Fixes: ec69541aaaba (Update to 1.1.10.5)