No longer concatenating extensions

Author: TheChymera

nipype/pipeline/engine/utils.py

@@ -1049,6 +1049,7 @@ def export_graph(graph_in, base_dir=None, show=False, use_execgraph=False,
 def format_dot(dotfilename, format='png'):
     """Dump a directed graph (Linux only; install via `brew` on OSX)"""
     if format != 'dot':
+        dotfilename = os.path.splitext(dotfilename)[0]
         cmd = 'dot -T%s -O \'%s\'' % (format, dotfilename)
         try:
             CommandLine(cmd).run()