Bitcode writer: fix a typo, using getName() instead of getSourceFileName()
Bitcode writer: fix a typo, using getName() instead of getSourceFileName()

When emitting the source filename, the encoding of the string
was checked against the name instead of the filename.

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@261019 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm