Prior to this patch, a Man in the Middle (MITM) attack on SSL could cause GMPInstallManager to fail during the check for updates, which in turn would cause a crash during shutdown. This was observed in the wild by users of recent versions of Avast, which performs such attacks on SSL as part of its "HTTPS scanning" feature. With this patch, errors are handled more gracefully. The attack still prevents any update (including the install of OpenH264) but at least it does not cause a crash anymore.
Certain usage scenarios, like enterprise roaming profile setups, lead to the installed OpenH264 plugin not being found anymore.
We install the plugin into the profile directory, so the fix here is to just store the install path relative the profile and not an absolute path.
We also now store the plugin in a version-specific subdirectory, which avoids further issues like e.g. Windows preventing updates due to locking loaded DLLs.
