HADOOP-10525. Remove DRFA.MaxBackupIndex config from log4j.properties (aajisaka)

(cherry picked from commit 03a5e04d5b6ec89219769868466e3b4913b0fff6)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -149,6 +149,9 @@ Release 2.7.0 - UNRELEASED
 
     HADOOP-11317. Increment SLF4J version to 1.7.10. (Tim Robertson via ozawa)
 
+    HADOOP-10525. Remove DRFA.MaxBackupIndex config from log4j.properties
+    (aajisaka)
+
   OPTIMIZATIONS
 
     HADOOP-11323. WritableComparator#compare keeps reference to byte array.

hadoop-common-project/hadoop-common/src/main/conf/log4j.properties

@@ -54,11 +54,9 @@ log4j.appender.RFA.layout.ConversionPattern=%d{ISO8601} %p %c: %m%n
 log4j.appender.DRFA=org.apache.log4j.DailyRollingFileAppender
 log4j.appender.DRFA.File=${hadoop.log.dir}/${hadoop.log.file}
 
-# Rollver at midnight
+# Rollover at midnight
 log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
 
-# 30-day backup
-#log4j.appender.DRFA.MaxBackupIndex=30
 log4j.appender.DRFA.layout=org.apache.log4j.PatternLayout
 
 # Pattern format: Date LogLevel LoggerName LogMessage