Renames RTD_VERSION_SLUG to READTHEDOCS_VERSION

Adds another environment var for the project slug.
Adds both to DockerEnvironment create_container function.

Author: rrahn

readthedocs/doc_builder/environments.py

@@ -90,7 +90,8 @@ def run(self):
         environment.update(self.environment)
         environment['READTHEDOCS'] = 'True'
         if self.build_env is not None:
-            environment['RTD_VERSION_SLUG'] = self.build_env.version.slug
+            environment['READTHEDOCS_VERSION'] = self.build_env.version.slug
+            environment['READTHEDOCS_PROJECT'] = self.build_env.project.slug
         if 'DJANGO_SETTINGS_MODULE' in environment:
             del environment['DJANGO_SETTINGS_MODULE']
         if 'PYTHONPATH' in environment:
@@ -541,6 +542,8 @@ def create_container(self):
                     }
                 }),
                 detach=True,
+                environment = {'READTHEDOCS_VERSION' : self.version.slug,
+                               'READTHEDOCS_PROJECT' : self.project.slug},
                 mem_limit=self.container_mem_limit,
             )
             client.start(container=self.container_id)