When you install CC 2014, it doesn't overwrite anything. CC (version 12) should still be on your computer.
There have been several threads about this. Adobe removed the option to encode directly into H.264 from After Effects (thus the term "deprecated" in the last version). The stated reason for the removal is that After Effects does not do a good job at encoding h.264 (due to the inherent nature of how the program works). Thus, the After Effects team removed it rather than continually spending development time on it when a much better solution is available.
The better solution is one that I've always used. I never liked how AE encoded h.264, so I never used it. I always render an intermediate file out of AE and then use the Adobe Media Encoder to create the h.264. I had several reasons for doing this. One reason is that AE can't do multipass encoding and that's something that can really help the quality of video in lower bitrates. Another reason is that I often need to try a few different iterations of compression to make sure I'm getting the highest possible quality at the lowest bitrate possible. As you're, no doubt, aware, it's a delicate balance between data rate and quality. Rendering a lossless intermediate from After Effects lets you try as many variations of compression you want without having to rerender your AE comp each time. If you've got 3d, motion blur, lots of particles, or anything that takes a while to render, this will make a lot of sense.
However, if you already know what settings you like, another great solution is to send your Adobe composition directly to the Adobe Media Encoder via Dynamic Link. This lets the AME begin rendering your AE comp in the background while you continue on to your next AE project and you are still taking advantage of multi-pass encoding if you wish.
So, there you go: two superior workflows even if Adobe hadn't removed the option.