Build(pynn-brainscales): Keep building after the initial fail

Let's try to find all build problems in one try… keep building after
the initial error to find additional ones.

packages/pynn-brainscales/package.py

@@ -127,3 +127,9 @@ class PynnBrainscales(WafPackage):
         args += self.configure_args()
 
         self.waf('configure', *args)
+
+    def build_args(self):
+        # keep going after fails
+        args = ['--keep']
+
+        return args