[201811] add bgpraw to show run all (#2603)

What I did
Backport #2537
Add bgpraw output to show runningconfiguration all

How I did it
Generate bgpraw output then append it to show runnningconfiguration all's output

How to verify it
There is not unit test support on such old version.
Manually test on 201811 image.

show/main.py

@@ -192,6 +192,11 @@ def run_command(command, display_cmd=False):
         sys.exit(rc)
 
 
+def get_cmd_output(cmd):
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    return proc.communicate()[0], proc.returncode
+
+
 def get_interface_mode():
     mode = os.getenv('SONIC_CLI_IFACE_MODE')
     if mode is None:
@@ -1322,8 +1327,24 @@ def runningconfiguration():
 @click.option('--verbose', is_flag=True, help="Enable verbose output")
 def all(verbose):
     """Show full running configuration"""
-    cmd = "sonic-cfggen -d --print-data"
-    run_command(cmd, display_cmd=verbose)
+    cmd = ['sonic-cfggen', '-d', '--print-data']
+    stdout, rc = get_cmd_output(cmd)
+    if rc:
+        click.echo("Failed to get cmd output '{}':rc {}".format(cmd, rc))
+        raise click.Abort()
+
+    try:
+        output = json.loads(stdout)
+    except ValueError as e:
+        click.echo("Failed to load output '{}':{}".format(cmd, e))
+        raise click.Abort()
+
+    bgpraw_cmd = ['rvtysh', '-c', 'show running-config']
+    bgpraw, rc = get_cmd_output(bgpraw_cmd)
+    if rc:
+        bgpraw = ""
+    output['bgpraw'] = bgpraw
+    click.echo(json.dumps(output, indent=4))
 
 
 # 'acl' subcommand ("show runningconfiguration acl")