Fix build with python disabled after r249597

Summary: r249597 introduced a usage of GetTypeSummary in lldb-mi.
That function used to only be available when python is enabled.
However, there is no reason for that anymore since that is now
dealt with at a different abstraction layer.

Reviewers: ki.stfu, evgeny777, clayborg, granata.enrico

Subscribers: elehcim, brucem, lldb-commits

Differential Revision: http://reviews.llvm.org/D13577

llvm-svn: 250494