Remove XFAIL on Linux test-repl-glibc test.

This is needed to get a clean bill of health on:
https://github.com/apple/swift/pull/2279
diff --git a/repl/test-repl-glibc.py b/repl/test-repl-glibc.py
index 457b14f..87972c5 100644
--- a/repl/test-repl-glibc.py
+++ b/repl/test-repl-glibc.py
@@ -1,7 +1,5 @@
 # Tests that importing Glibc works on Linux
 #
-# XFAIL: linux
-# TRACKED BY: SR-1109
 # REQUIRES: platform=Linux
 # REQUIRES: have-pexpect
 #