Also install the .pom file alongside the .jar file

## Summary

If there is a ".pom" file right next to the ".jar" file being installed, `localrepo install` will also install the ".pom" file into the local repository.

## Some details
Prior to this change, `localrepo` would merely install the specified jar file without a way to also install the coresponding .pom file. Such "pom-less" installs worked but caused warnings from `lein` whenever it resolved dependencies (e.g. during `deps` or `classpath` tasks).

Here's the example of warnings I got when I had `elasticsearch` installed locally but without its pom file:

```sh
$ lein deps 
Could not find artifact org.elasticsearch:elasticsearch:pom:0.19.8 in central (http://repo1.maven.org/maven2)
Could not find artifact org.elasticsearch:elasticsearch:pom:0.19.8 in clojars (https://clojars.org/repo/)
Could not find artifact org.elasticsearch:elasticsearch:jar:0.19.8 in central (http://repo1.maven.org/maven2)
Could not find artifact org.elasticsearch:elasticsearch:jar:0.19.8 in clojars (https://clojars.org/repo/)
```