from_sourcing_file: fixed a bug + added a few ignored variables

closes spack#7536

Credits for this change goes to @mgsternberg (original author of spack#7536)

The new variables being ignored are specific to Modules v4.

lib/spack/spack/util/environment.py

@@ -446,7 +446,12 @@ def from_sourcing_file(filename, *args, **kwargs):
                              for k, v in env_after.items())
 
         # Other variables unrelated to sourcing a file
-        blacklist.extend(['SHLVL', '_', 'PWD', 'OLDPWD', 'PS2'])
+        blacklist.extend([
+            # Bash internals
+            'SHLVL', '_', 'PWD', 'OLDPWD', 'PS2', 'ENV',
+            # Environment modules v4
+            'LOADEDMODULES', '_LMFILES_', 'BASH_FUNC_module()'
+        ])
 
         def set_intersection(fullset, *args):
             # A set intersection using string literals and regexs