Do include the depends field in the control file if and only if it wa…

…s set.

When the change to no longer include the default depends was made in tcurdt#209 to fix tcurdt#208 it entirely eliminated the ability to set the depends programatically. In fact, the field DebMaker.depends is never read.

src/main/java/org/vafer/jdeb/DebMaker.java

@@ -503,6 +503,12 @@ public BinaryPackageControlFile createSignedDeb(Compression compression, final P
             if (packageControlFile.get("Description") == null) {
                 packageControlFile.set("Description", description);
             }
+            if (packageControlFile.get("Depends") == null) {
+                // Only add a depends entry to the control file if the field in this object has actually been set
+                if (depends != null && depends.length() > 0) {
+                    packageControlFile.set("Depends", depends);
+                }
+            }
             if (packageControlFile.get("Homepage") == null) {
                 packageControlFile.set("Homepage", homepage);
             }