Since getDriver().getInstalledDir() returns a const char *, don't try to

compare it with getDriver().Dir.c_str(), since that is a pointer
comparison, not a "are these strings equal" comparison.

Instead, just compare with getDriver().Dir directly, so both sides will
get promoted to std::string, and the regular std::string comparison
operator applies.

Patch by Dimitry Andric!

llvm-svn: 126791