I agree with those who said that discovery of alien life is not going to spell the end for religion. Religion is far too deeply rooted in human nature in order to be wiped out by a single incident, however extraordinary that may be.
The ONLY way to bring religion to oblivion is through secular, scientific, religion-free, superstition-free education; this a long process that will take a lot more decades, and possibly centuries.
Even if we discover a million alien species, even if we shake hands with ET himself, religion & superstition will NOT fall, except if the former happens.
Expecting something like "First contact" to wipe out religion, tells that you're still under religion's spell, in the sense that you expect for a 'miracle' to happen, and make your wish come true, just like that.
STOP believing in miracles!