Update submodule location for llvm-pretty and dismantle

[mccleeary-galois]

Fix #81

[mccleeary-galois]

semmc is not compatible with the most recent version of crucible it appears, going to cut a ticket for that and leave it for now.

[kquick]

You should be able to change the location but keep the same hash reference, so that it's still building the same versions of the code. Then we can change the hash references to newer versions in a separate PR effort.

[RyanGlScott]

The failure doesn't really have anything to do with semmc itself—it's because you are bumping the llvm-pretty submodule to a version that is incompatible with crucible-llvm's upper bounds (where crucible-llvm is also vendored in via a submodule). These submodules would need to be updated in tandem.