Merge pull request #1893 from ryanpetrello/fix-broken-cancels

revert expect(use_poll=True) due to a bug that causes `os.read()` hangs

awx/main/expect/run.py

@@ -101,7 +101,7 @@ def run_pexpect(args, cwd, env, logfile,
 
     child = pexpect.spawn(
         args[0], args[1:], cwd=cwd, env=env, ignore_sighup=True,
-        encoding='utf-8', echo=False, use_poll=True
+        encoding='utf-8', echo=False
     )
     child.logfile_read = logfile
     canceled = False