Include slf4j and log4j in jgit command line

This enables the command line to log. Include log4j configuration to log
warnings and errors to stderr.

Exclude the dependencies which log4j 1.2.15 should have marked optional.
See
http://unitstep.net/blog/2009/05/18/resolving-log4j-1215-dependency-problems-in-maven-using-exclusions/
for details

Change-Id: Ie730db4007fb7614fd7d130cd0858b1ac550066a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm/pom.xml

       <artifactId>org.eclipse.jgit.ui</artifactId>
       <version>${project.version}</version>
     </dependency>
+
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <version>${slf4j-version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-log4j12</artifactId>
+      <version>${slf4j-version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>log4j</groupId>
+      <artifactId>log4j</artifactId>
+      <version>${log4j-version}</version>
+    </dependency>
   </dependencies>
 
   <build>

org.eclipse.jgit.pgm/resources/log4j.properties

+log4j.rootLogger=WARNING, stderr
+
+log4j.appender.stderr=org.apache.log4j.ConsoleAppender
+log4j.appender.stderr.Target=System.err
+log4j.appender.stderr.layout=org.apache.log4j.PatternLayout
+log4j.appender.stderr.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

pom.xml

         <groupId>log4j</groupId>
         <artifactId>log4j</artifactId>
         <version>${log4j-version}</version>
+        <exclusions>
+          <exclusion>
+            <groupId>javax.mail</groupId>
+            <artifactId>mail</artifactId>
+          </exclusion>
+          <exclusion>
+            <groupId>javax.jms</groupId>
+            <artifactId>jms</artifactId>
+          </exclusion>
+          <exclusion>
+            <groupId>com.sun.jdmk</groupId>
+            <artifactId>jmxtools</artifactId>
+          </exclusion>
+          <exclusion>
+            <groupId>com.sun.jmx</groupId>
+            <artifactId>jmxri</artifactId>
+          </exclusion>
+        </exclusions>
       </dependency>
     </dependencies>
   </dependencyManagement>