[tsan] Do nothing in ScopedInterceptor's destructor if thr is not inited.
[tsan] Do nothing in ScopedInterceptor's destructor if thr is not inited.

Summary:
It is part of http://reviews.llvm.org/D15301, but missed when I committed
that patch.

Reviewers: kubabrecka, kcc, eugenis, llvm-commits, dvyukov

Differential Revision: http://reviews.llvm.org/D16235

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@258021 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt