YARN-10407. Add phantomjsdriver.log to gitignore. (#2244)

.gitignore

@@ -52,6 +52,7 @@ patchprocess/
 hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/package-lock.json
 hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/yarn-error.log
 hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/placement/schema
+phantomjsdriver.log
 
 #robotframework outputs
 log.html