Change the wildcard import to explicit ones.

Change-Id: Ia7bc1c4b6b82c127e1e4e0e657f69d249684e8e6
Signed-off-by: Yunjie Li <yunjieli@google.com>

org.eclipse.jgit/src/org/eclipse/jgit/api/LogCommand.java

 import org.eclipse.jgit.revwalk.filter.MaxCountRevFilter;
 import org.eclipse.jgit.revwalk.filter.RevFilter;
 import org.eclipse.jgit.revwalk.filter.SkipRevFilter;
-import org.eclipse.jgit.treewalk.filter.*;
+import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
+import org.eclipse.jgit.treewalk.filter.PathFilter;
+import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
+import org.eclipse.jgit.treewalk.filter.TreeFilter;
 
 /**
  * A class used to execute a {@code Log} command. It has setters for all