Set LLDB_SESSION_DIRNAME to absolute path
Set LLDB_SESSION_DIRNAME to absolute path

This is to ensure that session files are written to the correct
directory if the -r option is given.

git-svn-id: b33bab8abb5b18c12ee100cd7761ab452d00b2b0@133483 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb