Fix SubobjectParserFunction name/class

Won't change any logic but fixed namimg in 1.9 to ensure
consitency among file and class names, and prepares to push [1]
into 1.10 right away

[1] https://gerrit.wikimedia.org/r/#/c/52598/

Change-Id: I492fd8e3a9ef6b77b83172638a80eb9313163902