use objects as String without calling the toString method

Our tool DeepTect has detected two buggy code snippets, in which the code prints out an object without calling the toString method:

Path: maven-scm/maven-scm-plugin/src/main/java/org/apache/maven/scm/plugin/ExportMojo.java

this.exportDirectory = new File( this.getBasedir(), "target/export" );
...
this.getLog().info( "Removing " + this.exportDirectory );
...
 throw new MojoExecutionException( "Cannot create " + this.exportDirectory );