commons logging printing time stamp as long instead of pretty date format

Question

I am using apache commons logging.

   <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.2</version>
    </dependency>

<dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>

The loggers used to print the date like this

  20-Aug-2015 13:15:39.740 INFO [http-nio-8080-exec-3] com.myapp.myclass Method 'mymethod' executed. Processing time: 2 ms

But now it prints like this

      91522432 [http-nio-8080-exec-3] INFO com.myapp.myclass Method 'mymethod' executed. Processing time: 2 ms <br/>

Warnings in the log:

   SLF4J: The requested version 1.5.8 by your slf4j binding is not  compatible with [1.6]
   SLF4J: See http://www.slf4j.org/codes.html#version_mismatch for further details

There is a clash because the spring-data-jpa imports another version. how do i exclude that in pom?