Backwards compatibility type synonym for InstalledPackageId.
Backwards compatibility type synonym for InstalledPackageId.

Signed-off-by: Edward Z. Yang <dbd597f5635f432486c5d365e9bb585b3eaa1853@cs.stanford.edu>

mydaum/cabal,kolmodin/cabal,bennofs/cabal,randen/cabal,trskop/cabal,thomie/cabal,thoughtpolice/cabal,thoughtpolice/cabal,edsko/cabal,sopvop/cabal,thomie/cabal,enolan/cabal,garetxe/cabal,trskop/cabal,lukexi/cabal,bennofs/cabal,sopvop/cabal,gbaz/cabal,randen/cabal,kolmodin/cabal,mmakowski/cabal,headprogrammingczar/cabal,themoritz/cabal,lukexi/cabal,garetxe/cabal,Peaker/cabal,themoritz/cabal,Heather/cabal,mmakowski/cabal,martinvlk/cabal,edsko/cabal,enolan/cabal,gbaz/cabal,martinvlk/cabal,Heather/cabal,headprogrammingczar/cabal,sopvop/cabal,Peaker/cabal,mydaum/cabal,themoritz/cabal