Fix currentSrc when Flash returns null
It looks like GCC was mangling `rtmpConnection` and `rtmpStream` before invoking them. Unfortunately, we define those methods as string literals so they do not have mangled equivalents. Invoke them using string literals so GCC never mangles the method names.
Merge pull request #1116 from dmlap/hotfix/gcc-currentSrc

Fix currentSrc when Flash returns null