Remove 'set -ex' from execute_commands

Remove this setting to not fail on the steps
which are not ready to this change

Change-Id: I482bca0ff285d45bbc013855a16b21fec58cbba8
diff --git a/tcp_tests/managers/execute_commands.py b/tcp_tests/managers/execute_commands.py
index a8cea3d..991fb58 100644
--- a/tcp_tests/managers/execute_commands.py
+++ b/tcp_tests/managers/execute_commands.py
@@ -101,7 +101,7 @@
                 LOG.info("\n\n{0}\n{1}".format(
                     msg + retry_msg, '=' * len(msg + retry_msg)))
 
-                result = remote.execute('set -ex; ' + cmd, verbose=True)
+                result = remote.execute(cmd, verbose=True)
 
                 # Workaround of exit code 0 from salt in case of failures
                 failed = 0