don't dereference hte end iterator when inserting at end of buffer. Patch by Cédric Venet!
don't dereference hte end iterator when inserting at end of buffer.
Patch by Cédric Venet!


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@49259 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang