[java][okhttp-gson] Remove errorObjectType as it's not used

Remove errorObjectType as it's not used

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cc @bbdouglas (2017/07) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09) @jeff9finger (2018/01) @karismann (2019/03) @Zomzog (2019/04) @lwlee2608 (2019/10)

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache

@@ -333,7 +333,6 @@ public class {{classname}} {
             return localVarApiClient.executeStream(localVarCall, localVarReturnType);
         } catch (ApiException e) {
             e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<{{{errorObjectType}}}>(){}.getType()));
-            e.setErrorObjectType(new GenericType<{{{errorObjectType}}}>(){});
             throw e;
         }
         {{/errorObjectType}}
@@ -355,7 +354,6 @@ public class {{classname}} {
             return localVarApiClient.execute(localVarCall, localVarReturnType);
         } catch (ApiException e) {
             e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<{{{errorObjectType}}}>(){}.getType()));
-            e.setErrorObjectType(new GenericType<{{{errorObjectType}}}>(){});
             throw e;
         }
         {{/errorObjectType}}

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/apiException.mustache

@@ -22,7 +22,6 @@ public class ApiException extends{{#useRuntimeException}} RuntimeException {{/us
     private String responseBody = null;
     {{#errorObjectType}}
     private {{{errorObjectType}}} errorObject = null;
-    private GenericType errorObjectType = null;
     {{/errorObjectType}}
  
     /**
@@ -174,24 +173,6 @@ public class ApiException extends{{#useRuntimeException}} RuntimeException {{/us
     }
     {{#errorObjectType}}
 
-    /**
-     * Get the error object type.
-     *
-     * @return Error object type
-     */
-    public GenericType getErrorObjectType() {
-        return errorObjectType;
-    }
-
-    /**
-     * Set the error object type.
-     *
-     * @param errorObjectType object type
-     */
-    public void setErrorObjectType(GenericType errorObjectType) {
-        this.errorObjectType = errorObjectType;
-    }
-
     /**
      * Get the error object.
      *