fix a little error that caused the completion not to work with if/try statements

parsing.py

@@ -1370,9 +1370,14 @@ class PyFuzzyParser(object):
                             # the last statement has to be another part of
                             # the flow statement, because a dedent releases the
                             # main scope, so just take the last statement.
-                            self.scope = self.scope.statements[-1].set_next(f)
+                            try:
+                                s = self.scope.statements[-1].set_next(f)
+                            except AttributeError:
+                                # If set_next doesn't exist, just add it.
+                                s = self.scope.add_statement(f)
                         else:
-                            self.scope = self.scope.add_statement(f)
+                            s = self.scope.add_statement(f)
+                        self.scope = s
                     else:
                         debug.warning('syntax err, flow started @%s',
                                                             self.line_nr)

test/completion/invalid.py

@@ -27,3 +27,19 @@ def normalfunc():
 
 ##? ['real']
 normalfunc().real
+
+
+# first part not complete (raised errors)
+if a
+    a
+else:
+    #? ['AttributeError']
+    AttributeError
+
+try
+#? ['AttributeError']
+except AttributeError
+    pass
+finally:
+    pass
+