kconfiglib: Fix file leaks

Fixing a couple cases of a programming error where a file is not closed
in case of an exception, which was causing resource leak warnings in
some cases when encountering a kconfig error.

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>
Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

Author: Declan Snyder

kconfiglib.py

@@ -1145,10 +1145,10 @@ def _init(
             self.top_node.next = None
         except UnicodeDecodeError as e:
             _decoding_error(e, self.filename)
-
-        # Close the top-level Kconfig file. __self__ fetches the 'file' object
-        # for the method.
-        self._readline.__self__.close()
+        finally:
+            # Close the top-level Kconfig file. __self__ fetches the 'file' object
+            # for the method.
+            self._readline.__self__.close()
 
         self._parsing_kconfigs = False
 
@@ -3112,8 +3112,10 @@ def _parse_block(self, end_token, parent, prev):
 
                 for filename in filenames:
                     self._enter_file(filename)
-                    prev = self._parse_block(None, parent, prev)
-                    self._leave_file()
+                    try:
+                        prev = self._parse_block(None, parent, prev)
+                    finally:
+                        self._leave_file()
 
             elif t0 is end_token:
                 # Reached the end of the block. Terminate the final node and