HtmlUnitPlugin was missing a dependency context (#212)

Author: sbabcoc

src/selenium2/java/com/nordstrom/automation/selenium/plugins/HtmlUnitPlugin.java

@@ -41,7 +41,8 @@ public HtmlUnitPlugin() {
                     "org.eclipse.jetty.websocket.client.WebSocketClient",
                     "org.eclipse.jetty.util.IO", "org.eclipse.jetty.io.EndPoint",
                     "org.eclipse.jetty.websocket.common.Parser",
-                    "org.eclipse.jetty.websocket.api.Session"};
+                    "org.eclipse.jetty.websocket.api.Session",
+                    "org.apache.commons.exec.Executor"};
 
     private static final String WEB_ELEMENT_CLASS_NAME =
             "org.openqa.selenium.htmlunit.HtmlUnitWebElement";

src/selenium3/java/com/nordstrom/automation/selenium/plugins/HtmlUnitPlugin.java

@@ -43,7 +43,8 @@ public HtmlUnitPlugin() {
                     "net.sourceforge.htmlunit.cyberneko.filters.DefaultFilter",
                     "org.apache.xmlcommons.Version", "com.gargoylesoftware.css.util.LangUtils",
                     "org.apache.commons.net.io.Util", "org.eclipse.jetty.client.Origin",
-                    "org.eclipse.jetty.http.Syntax", "org.brotli.dec.Utils"};
+                    "org.eclipse.jetty.http.Syntax", "org.brotli.dec.Utils",
+                    "org.apache.commons.exec.Executor"};
 
     private static final String WEB_ELEMENT_CLASS_NAME =
             "org.openqa.selenium.htmlunit.HtmlUnitWebElement";