Fix exception when alias is unresolvable

Author: salkinium

Diff for: lbuild/main.py

@@ -22,7 +22,7 @@
 
 from lbuild.api import Builder
 
-__version__ = '1.21.7'
+__version__ = '1.21.8'
 
 
 class InitAction:

Diff for: lbuild/node.py

@@ -134,7 +134,7 @@ def _get_node(self, key, check_dependencies=False, raise_on_fail=True):
             try:
                 node = context_resolver._get_node(node._destination)
                 warning += node.description + "\n"
-            except LbuildException as e:
+            except le.LbuildException as e:
                 LOGGER.warning(warning)
                 raise e
             if alias._print_warning: