[Issue_69] Prevent cat globbing if filenames contains wildcards

I ran into the same problem as the one described, this fixed it for me.

Example:
<pre>
concat { 'test': path => '/tmp/test' }
concat::fragment { 'one-other': target => 'test', content => "one-other\n" }
concat::fragment { '*-test': target => 'test', content => "*-test\n" }
concat::fragment { 'one-test': target => 'test', content => "one-test\n" }
</pre>

This would result in the file /tmp/test containing the following:

Actual:
<pre>
one-other
*-test
one-test
one-test
one-test
</pre>

Expected:
<pre>
one-other
*-test
one-test
</pre>