Fix locating gem when bundle show process outputs warnings

[asok]

On my project bundle show --path gives such output:

Your Gemfile lists the gem rack-mini-profiler (>= 0) more than once.
You should probably keep only one of them.
Remove any duplicate entries and specify the gem only once (per group).
While it's not a problem now, it could cause errors if you change the version of one of them later.
/Users/asok/.gem/ruby/2.6.3/gems/actioncable-6.0.2.1

This output breaks the command bundle-open.

The change assumes that the last line contains the actual path to the gem, the rest is ignored.
My change also removes the local variable remote. I'm not quite sure what is the purpose of it? When it was t and passing it as a first argument to concat is causing an error.