Remove an unused field from AbstractPostProcessor

--
MOS_MIGRATED_REVID=114985098

src/java_tools/buildjar/java/com/google/devtools/build/buildjar/AbstractPostProcessor.java

diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/AbstractPostProcessor.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/AbstractPostProcessor.java
index a028fcf..2e2ba47 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/AbstractPostProcessor.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/AbstractPostProcessor.java
@@ -40,7 +40,6 @@
     postProcessors.put(name, postProcessor);
   }
 
-  private String workingDir = null;
   private JavaLibraryBuildRequest build = null;
 
   /**
@@ -64,9 +63,7 @@
 
   protected String workingPath(String name) {
     Preconditions.checkNotNull(this.build);
-    return workingDir != null && name.length() > 0 && name.charAt(0) != '/'
-        ? workingDir + File.separator + name
-        : name;
+    return name;
   }
 
   protected boolean shouldCompressJar() {