obmc-phosphor-sysd: using shell script as a dummy implementation

For evb-ast2500/evb-ast2600 machine, Python are introduced by
obmc-phosphor-sysd.py. Changing the implementation to shell script
can remove python completely from image.

Test with evb-ast2600:
```
root@evb-ast2500:~# systemctl status obmc-phosphor-sysd
* obmc-phosphor-sysd.service - Phosphor System Manager
     Loaded: loaded (8;;file://evb-ast2500/lib/systemd/system/obmc-phosphor-sysd.service/lib/systemd/system/obmc)
     Active: active (running) since Thu 1970-01-01 00:00:38 UTC; 51 years 9 months ago
   Main PID: 168 (obmc-phosphor-s)
     CGroup: /system.slice/obmc-phosphor-sysd.service
             |-168 /bin/sh /usr/bin/obmc-phosphor-sysd
             `-312 sleep 60

Jan 01 00:00:38 evb-ast2500 systemd[1]: Started Phosphor System Manager.
Jan 01 00:00:40 evb-ast2500 obmc-phosphor-sysd[168]: obmc-phosphor-sysd starting...
```

Signed-off-by: Troy Lee <troy_lee@aspeedtech.com>
Change-Id: I266bd73773483d5ceb2ba01a09d372942eddc939
diff --git a/meta-phosphor/recipes-phosphor/system/obmc-phosphor-sysd/obmc-phosphor-sysd.sh b/meta-phosphor/recipes-phosphor/system/obmc-phosphor-sysd/obmc-phosphor-sysd.sh
new file mode 100644
index 0000000..95488d0
--- /dev/null
+++ b/meta-phosphor/recipes-phosphor/system/obmc-phosphor-sysd/obmc-phosphor-sysd.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+# Contributors Listed Below - COPYRIGHT 2015
+# [+] International Business Machines Corp.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License.
+
+echo "obmc-phosphor-sysd starting..."
+
+while true
+do
+	sleep 60
+done