Eliminate need for bash

Index: terminado/tests/basic_test.py
--- terminado/tests/basic_test.py.orig
+++ terminado/tests/basic_test.py
@@ -158,14 +158,14 @@ class TermTestCase(tornado.testing.AsyncHTTPTestCase):
 
     def get_app(self):
         self.named_tm = NamedTermManager(
-            shell_command=["bash"],
+            shell_command=["ksh"],
             max_terminals=MAX_TERMS,
         )
 
-        self.single_tm = SingleTermManager(shell_command=["bash"])
+        self.single_tm = SingleTermManager(shell_command=["ksh"])
 
         self.unique_tm = UniqueTermManager(
-            shell_command=["bash"],
+            shell_command=["ksh"],
             max_terminals=MAX_TERMS,
         )