email2pdf: header file path was hardcoded

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk/contrib@15771 d0543943-73ff-0310-b7d9-9358b9ac24b2

sathieu/email2pdf/email2pdf

@@ -201,7 +201,7 @@ sub process_header
 	};
 
 	# specify input filename, or file handle, text reference, etc.
-	my $content_type = `file --mime-type --brief header.html`;
+	my $content_type = `file --mime-type --brief $o_header`;
 	$content_type =~ s/\s+$//; # trim end whitespace
 	my $header = '';