make value parameter of the updateConfiguration API required

Author: bernardodemarco

api/src/main/java/org/apache/cloudstack/api/command/admin/config/UpdateCfgCmd.java

@@ -48,7 +48,7 @@ public class UpdateCfgCmd extends BaseCmd {
     @Parameter(name = ApiConstants.NAME, type = CommandType.STRING, required = true, description = "the name of the configuration")
     private String cfgName;
 
-    @Parameter(name = ApiConstants.VALUE, type = CommandType.STRING, description = "the value of the configuration", length = 4096)
+    @Parameter(name = ApiConstants.VALUE, type = CommandType.STRING, required = true, description = "the value of the configuration", length = 4096)
     private String value;
 
     @Parameter(name = ApiConstants.ZONE_ID,

server/src/main/java/com/cloud/configuration/ConfigurationManagerImpl.java

@@ -975,10 +975,6 @@ public Configuration updateConfiguration(final UpdateCfgCmd cmd) throws InvalidP
             throw new CloudRuntimeException("Only Root Admin is allowed to edit this configuration.");
         }
 
-        if (value == null) {
-            return _configDao.findByName(name);
-        }
-
         String scope = null;
         Long id = null;
         int paramCountCheck = 0;