Wire up the webclient option

It existed but was hardcoded to True.
Give it an underscore for consistency.
Also don't pull in syweb unless we're actually using the web client.

synapse/app/homeserver.py

@@ -60,7 +60,6 @@ import re
 import resource
 import subprocess
 import sqlite3
-import syweb
 
 logger = logging.getLogger(__name__)
 
@@ -83,6 +82,7 @@ class SynapseHomeServer(HomeServer):
         return AppServiceRestResource(self)
 
     def build_resource_for_web_client(self):
+        import syweb
         syweb_path = os.path.dirname(syweb.__file__)
         webclient_path = os.path.join(syweb_path, "webclient")
         return File(webclient_path)  # TODO configurable?
@@ -130,7 +130,7 @@ class SynapseHomeServer(HomeServer):
             True.
         """
         config = self.get_config()
-        web_client = config.webclient
+        web_client = config.web_client
 
         # list containing (path_str, Resource) e.g:
         # [ ("/aaa/bbb/cc", Resource1), ("/aaa/dummy", Resource2) ]
@@ -343,7 +343,8 @@ def setup(config_options):
 
     config.setup_logging()
 
-    check_requirements()
+    # check any extra requirements we have now we have a config
+    check_requirements(config)
 
     version_string = get_version_string()
 
@@ -450,6 +451,7 @@ def run(hs):
 
 def main():
     with LoggingContext("main"):
+        # check base requirements
         check_requirements()
         hs = setup(sys.argv[1:])
         run(hs)