Fixed ModuleNotFoundError during 'make'.

The eps.so was loaded by __init__.py during making
the shared object and was obviously not found.
The import is now enclose in a try...except block to
avoid raising an exception.

src/python/msspec_dfm/__init__.py

@@ -21,4 +21,7 @@
 # Committed by : Sylvain Tricot <sylvain.tricot@univ-rennes1.fr> 1645806435 +0100
 
 from msspec_dfm.version import __version__
-from msspec_dfm.compute import compute
+try:
+    from msspec_dfm.compute import compute
+except ModuleNotFoundError as err:
+    pass