[msan] Correct @LINE expression in obstack.cc
[msan] Correct @LINE expression in obstack.cc

Summary:

[[@LINE-30]] only worked because the resulting 3 matches the first character of
30. With the additional blank lines the resulting 5 no longer matches 30.

Reviewers: eugenis

Subscribers: eugenis, llvm-commits

Differential Revision: https://reviews.llvm.org/D23515


git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@278715 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