[build] explicitly add http-client dependency

As discussed in the PR https://github.com/elastic/elasticsearch/pull/12036#issuecomment-119584570

plugins/cloud-aws/pom.xml

@@ -33,6 +33,13 @@
             <artifactId>aws-java-sdk-s3</artifactId>
             <version>${amazonaws.version}</version>
         </dependency>
+        <!-- We need to force here the compile scope as it was defined as test scope in plugins/pom.xml -->
+        <!-- TODO: remove this dependency when we will have a REST Test module -->
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <build>

plugins/cloud-azure/pom.xml

@@ -55,6 +55,13 @@ governing permissions and limitations under the License. -->
             <artifactId>azure-management</artifactId>
             <version>0.7.0</version>
         </dependency>
+        <!-- We need to force here the compile scope as it was defined as test scope in plugins/pom.xml -->
+        <!-- TODO: remove this dependency when we will have a REST Test module -->
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <build>

plugins/cloud-gce/pom.xml

@@ -48,6 +48,13 @@ governing permissions and limitations under the License. -->
               </exclusion>
           </exclusions>
         </dependency>
+        <!-- We need to force here the compile scope as it was defined as test scope in plugins/pom.xml -->
+        <!-- TODO: remove this dependency when we will have a REST Test module -->
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <build>

plugins/delete-by-query/pom.xml

@@ -31,16 +31,6 @@ governing permissions and limitations under the License. -->
         <tests.rest.load_packaged>false</tests.rest.load_packaged>
     </properties>
 
-    <dependencies>
-        <!-- Required by the REST test framework -->
-        <!-- Note that we should have this as a transient dependency coming from test module if any -->
-        <dependency>
-            <groupId>org.apache.httpcomponents</groupId>
-            <artifactId>httpclient</artifactId>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
     <build>
         <plugins>
             <plugin>

plugins/pom.xml

@@ -214,6 +214,14 @@
             <artifactId>jna</artifactId>
             <scope>provided</scope>
         </dependency>
+
+        <!-- Required by the REST test framework -->
+        <!-- TODO: remove this dependency when we will have a REST Test module -->
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <!-- typical layout for plugins -->