replace host check command in e1031 (sonic-net#18279)

device/celestica/x86_64-cel_e1031-r0/sonic_platform/common.py

@@ -24,7 +24,6 @@ class Common:
 
     SET_METHOD_IPMI = 'ipmitool'
     NULL_VAL = 'N/A'
-    HOST_CHK_CMD = ["docker"]
     REF_KEY = '$ref:'
 
     def __init__(self, conf=None):
@@ -184,12 +183,13 @@ def write_txt_file(self, file_path, value):
             return False
         return True
 
-    def is_host(self):
-        try:
-            subprocess.call(self.HOST_CHK_CMD, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
-        except FileNotFoundError:
-            return False
-        return True
+    def is_host():
+        """
+        Test whether current process is running on the host or an docker
+        return True for host and False for docker
+        """
+        docker_env_file = '/.dockerenv'
+        return os.path.exists(docker_env_file) is False
 
     def load_json_file(self, path):
         """