gh-93692: remove "build finished successfully" message from setup.py (#93693)

The message was only emitted when the build succeeded _and_ there were
missing modules.

Author: erlend-aasland

setup.py

@@ -538,7 +538,6 @@ def print_three_column(lst):
 
         if self.missing:
             print()
-            print("Python build finished successfully!")
             print("The necessary bits to build these optional modules were not "
                   "found:")
             print_three_column(self.missing)