Revert "Move calculation of normalised uri to the codepath where it is actually used"

This reverts commit 1504fc60e4b676aeec2ccc3121d7462bc885545f.
diff --git a/mako/template.py b/mako/template.py
index bb5d891..3a7b7f0 100644
--- a/mako/template.py
+++ b/mako/template.py
@@ -255,6 +255,16 @@
             self.module_id = "memory:" + hex(id(self))
             self.uri = self.module_id
 
+        u_norm = self.uri
+        if u_norm.startswith("/"):
+            u_norm = u_norm[1:]
+        u_norm = os.path.normpath(u_norm)
+        if u_norm.startswith(".."):
+            raise exceptions.TemplateLookupException(
+                    "Template uri \"%s\" is invalid - "
+                    "it cannot be relative outside "
+                    "of the root path." % self.uri)
+
         self.input_encoding = input_encoding
         self.output_encoding = output_encoding
         self.encoding_errors = encoding_errors
@@ -300,16 +310,6 @@
             if module_filename is not None:
                 path = module_filename
             elif module_directory is not None:
-                u_norm = self.uri
-                if u_norm.startswith("/"):
-                    u_norm = u_norm[1:]
-                u_norm = os.path.normpath(u_norm)
-                if u_norm.startswith(".."):
-                    raise exceptions.TemplateLookupException(
-                            "Template uri \"%s\" is invalid - "
-                            "it cannot be relative outside "
-                            "of the root path." % self.uri)
-
                 path = os.path.abspath(
                         os.path.join(
                             os.path.normpath(module_directory),