Remove unnecessary Host header set in UriModifyingOperationPreprocessor

Closes gh-280

Author: izeye

spring-restdocs-restassured/src/main/java/org/springframework/restdocs/restassured/operation/preprocess/UriModifyingOperationPreprocessor.java

@@ -126,10 +126,8 @@ public OperationRequest preprocess(OperationRequest request) {
 if (this.scheme != null) {
 uriBuilder.scheme(this.scheme);
 }
-HttpHeaders modifiedHeaders = modify(request.getHeaders());
 if (this.host != null) {
 uriBuilder.host(this.host);
-modifiedHeaders.set(HttpHeaders.HOST, this.host);
 }
 if (this.port != null) {
 if (StringUtils.hasText(this.port)) {
@@ -140,6 +138,7 @@ public OperationRequest preprocess(OperationRequest request) {
 }
 }
 URI modifiedUri = uriBuilder.build(true).toUri();
+HttpHeaders modifiedHeaders = modify(request.getHeaders());
 modifiedHeaders.set(HttpHeaders.HOST, modifiedUri.getHost()
 + (modifiedUri.getPort() == -1 ? "" : ":" + modifiedUri.getPort()));
 return this.contentModifyingDelegate.preprocess(