Removed weird XML comment in omux.pb_type.xml, fixed mux_gen.py to generate correct comments.

Signed-off-by: Maciej Kurc <mkurc@antmicro.com>

tests/vtr/lutff-pair/omux/omux.model.xml

diff --git a/tests/vtr/lutff-pair/omux/omux.model.xml b/tests/vtr/lutff-pair/omux/omux.model.xml
index ce22797..4d5beb1 100644
--- a/tests/vtr/lutff-pair/omux/omux.model.xml
+++ b/tests/vtr/lutff-pair/omux/omux.model.xml
@@ -1 +1 @@
-<models><!-- No models for routing elements.--></models>
\ No newline at end of file
+<models><!-- No models for routing elements.--></models>

tests/vtr/lutff-pair/omux/omux.pb_type.xml

diff --git a/tests/vtr/lutff-pair/omux/omux.pb_type.xml b/tests/vtr/lutff-pair/omux/omux.pb_type.xml
index 76a9987..c435bc0 100644
--- a/tests/vtr/lutff-pair/omux/omux.pb_type.xml
+++ b/tests/vtr/lutff-pair/omux/omux.pb_type.xml
@@ -3,23 +3,6 @@
     <meta name="type">bel</meta>
     <meta name="subtype">routing</meta>
   </metadata>
-  <!--
-    Generated with P
-    y
-    t
-    h
-    o
-    n
-     
-    f
-    u
-    n
-    c
-    t
-    i
-    o
-    n
-    -->
   <input name="L" num_pins="1"/>
   <input name="F" num_pins="1"/>
   <output name="O" num_pins="1"/>

v2x/mux_gen.py

diff --git a/v2x/mux_gen.py b/v2x/mux_gen.py
index c16ea80..a742125 100755
--- a/v2x/mux_gen.py
+++ b/v2x/mux_gen.py
@@ -146,7 +146,7 @@
 )
 
 
-def mux_gen(argv='Python function',
+def mux_gen(argv=('Python function', ),
             width=8,
             data_width=1,
             datatype='logic',