The same template content but with different destinations outputed only once

I have following two template files:
```
template.1
template.2
```
Both have the same content:
```
cat template.1
> aaa
cat template.2
> aaa
```
I run command:
```
./consul-template -template "./template.1:./template.1.out" -template "./template.2:./template.2.out" -once
```
As a result of this i receive one output file:
```
cat template.1.out
> aaa
```

Although i understand that template is resolved exactly once because it is basically the same but i expect it to be outputed into two destinations

If i remove "-once" arg from commandline than template is outputed as i expetcted into two destinations but as a consequence of this consul template process does not end and exit after templates resolving.

So i need both:
- outputing templates to each defined locations (even if they have the same content)
- exiting process after templates resolving

How to achive this? Is this a bug or intended behavior? And if intended behavior then may i ask for improvement and adding some additional mode or arg that will cause consul template to work as described above?

Reproduce the two-template command with and without -once, using the template files and destinations shown in the issue. Trace the -once command-line handling and rendering flow to determine why identical content is emitted once; done means both output files are written and the process exits after rendering.

Written by the indexing model from the issue text.