[LTO API] fix memory leakage introduced at r230290.

r230290 released the LLVM module but not the LTOModule.

rdar://19024554


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230544 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed