utils.py: use EnvironmentError

bilby/core/utils.py

@@ -359,8 +359,8 @@ def get_version_information():
     try:
         with open(version_file, 'r') as f:
             return f.readline().rstrip()
-    except IOError:
-        raise IOError("No version information file '.version' found")
+    except EnvironmentError:
+        print("No version information file '.version' found")
 
 
 def get_progress_bar(module='tqdm'):