[SPARK-8027] [SPARKR] Add maven profile to build R package docs

Also use that profile in create-release.sh

cc pwendell -- Note that this means that we need `knitr` and `roxygen` installed on the machines used for building the release. Let me know if you need help with that.

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes #6567 from shivaram/SPARK-8027 and squashes the following commits:

8dc8ecf [Shivaram Venkataraman] Add maven profile to build R package docs Also use that profile in create-release.sh

core/pom.xml

@@ -481,6 +481,29 @@
         </plugins>
       </build>
     </profile>
+    <profile>
+      <id>sparkr-docs</id>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.codehaus.mojo</groupId>
+            <artifactId>exec-maven-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>sparkr-pkg-docs</id>
+                <phase>compile</phase>
+                <goals>
+                  <goal>exec</goal>
+                </goals>
+              </execution>
+            </executions>
+            <configuration>
+              <executable>..${path.separator}R${path.separator}create-docs${script.extension}</executable>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
   </profiles>
 
 </project>

dev/create-release/create-release.sh

@@ -228,14 +228,14 @@ if [[ ! "$@" =~ --skip-package ]]; then
 
   # We increment the Zinc port each time to avoid OOM's and other craziness if multiple builds
   # share the same Zinc server.
-  make_binary_release "hadoop1" "-Psparkr -Phadoop-1 -Phive -Phive-thriftserver" "3030" &
-  make_binary_release "hadoop1-scala2.11" "-Psparkr -Phadoop-1 -Phive -Dscala-2.11" "3031" &
-  make_binary_release "cdh4" "-Psparkr -Phadoop-1 -Phive -Phive-thriftserver -Dhadoop.version=2.0.0-mr1-cdh4.2.0" "3032" &
-  make_binary_release "hadoop2.3" "-Psparkr -Phadoop-2.3 -Phive -Phive-thriftserver -Pyarn" "3033" &
-  make_binary_release "hadoop2.4" "-Psparkr -Phadoop-2.4 -Phive -Phive-thriftserver -Pyarn" "3034" &
-  make_binary_release "mapr3" "-Pmapr3 -Psparkr -Phive -Phive-thriftserver" "3035" &
-  make_binary_release "mapr4" "-Pmapr4 -Psparkr -Pyarn -Phive -Phive-thriftserver" "3036" &
-  make_binary_release "hadoop2.4-without-hive" "-Psparkr -Phadoop-2.4 -Pyarn" "3037" &
+  make_binary_release "hadoop1" "-Psparkr -Psparkr-docs -Phadoop-1 -Phive -Phive-thriftserver" "3030" &
+  make_binary_release "hadoop1-scala2.11" "-Psparkr -Psparkr-docs -Phadoop-1 -Phive -Dscala-2.11" "3031" &
+  make_binary_release "cdh4" "-Psparkr -Psparkr-docs -Phadoop-1 -Phive -Phive-thriftserver -Dhadoop.version=2.0.0-mr1-cdh4.2.0" "3032" &
+  make_binary_release "hadoop2.3" "-Psparkr -Psparkr-docs  -Phadoop-2.3 -Phive -Phive-thriftserver -Pyarn" "3033" &
+  make_binary_release "hadoop2.4" "-Psparkr -Psparkr-docs -Phadoop-2.4 -Phive -Phive-thriftserver -Pyarn" "3034" &
+  make_binary_release "mapr3" "-Pmapr3 -Psparkr -Psparkr-docs -Phive -Phive-thriftserver" "3035" &
+  make_binary_release "mapr4" "-Pmapr4 -Psparkr -Psparkr-docs -Pyarn -Phive -Phive-thriftserver" "3036" &
+  make_binary_release "hadoop2.4-without-hive" "-Psparkr -Psparkr-docs -Phadoop-2.4 -Pyarn" "3037" &
   wait
   rm -rf spark-$RELEASE_VERSION-bin-*/