[gnome-builder] eslint: Don't crash if eslint message does not contain a line

[Giovanni Campagna <gcampagna src gnome org>]

commit 8ba1533dd22d2d50d8b80f32c2ccb75dda14e23a
Author: Giovanni Campagna <gcampagn cs stanford edu>
Date:   Sat Nov 25 16:17:29 2017 -0800

    eslint: Don't crash if eslint message does not contain a line
    
    Just skip the message and process the rest of the output
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790834

 src/plugins/eslint/eslint_plugin.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/plugins/eslint/eslint_plugin.py b/src/plugins/eslint/eslint_plugin.py
index fbae269..a6926a1 100644
--- a/src/plugins/eslint/eslint_plugin.py
+++ b/src/plugins/eslint/eslint_plugin.py
@@ -94,6 +94,8 @@ class ESLintDiagnosticProvider(Ide.Object, Ide.DiagnosticProvider):
             results = json.loads(stdout)
             for result in results:
                 for message in result.get('messages', []):
+                    if 'line' not in message or 'column' not in message:
+                        continue
                     start_line = max(message['line'] - 1, 0)
                     start_col = max(message['column'] - 1, 0)
                     start = Ide.SourceLocation.new(file, start_line, start_col, 0)