TEIIDDES-2678: Fix for correct handling of vdb udf files

* VdbEntry
* VdbFileEntry
 * The path of the entry on windows will contain backslashes and these are
   not handled by jar files as file separators. Thus, the jar entry is not
   located in sub-directories but simply labelled with the full path.
 * Replace all backslashes with forward slashes to correctly handle file
   separators for jar entries

* XmiVdb
 * Ensures streams are not left open when jar archive reading and writing
 * Important on windows since it locks open files and the archive cannot
   be replaced with the temporary one at the conclusion of the save method

* MockFileBuilder
 * Avoids creating a FileInputStream unless absolutely required.

* VdbTest
 * Additional checks for ensuring udf jar is read and written correctly

plugins/org.teiid.designer.vdb/src/org/teiid/designer/vdb/VdbEntry.java

@@ -243,9 +243,15 @@ public boolean equals(Object obj) {
      */
     public void save( final ZipOutputStream out) throws Exception {
     	String zipName = getPath().toString();
+        //
+        // Path on Windows will be using backslashes but zip entries only
+        // deal with forward slashes so need to replace with them.
+        //
+        zipName = zipName.replace(DOUBLE_BACK_SLASH, FORWARD_SLASH);
+
     	// Need to strip off the leading delimeter if it exists, else a "jar" extract command will result in models
     	// being located at the file system "root" folder.
-    	if( zipName.startsWith("/") ) { //$NON-NLS-1$
+        if (zipName.startsWith(FORWARD_SLASH)) {
     		zipName = zipName.substring(1, zipName.length());
     	}
         final ZipEntry zipEntry = new ZipEntry(zipName);

plugins/org.teiid.designer.vdb/src/org/teiid/designer/vdb/VdbFileEntry.java

@@ -179,6 +179,13 @@ public IFile findFileInWorkspace() {
     public void save( final ZipOutputStream out) throws Exception {
         // Name of VDB entry
         String zipName = getPath().toOSString();
+
+        //
+        // Path on Windows will be using backslashes but zip entries only
+        // deal with forward slashes so need to replace with them.
+        //
+        zipName = zipName.replace(DOUBLE_BACK_SLASH, FORWARD_SLASH);
+
         // Need to strip off the leading delimeter if it exists, else a "jar" extract command will result in models
         // being located at the file system "root" folder.
         if(zipName.startsWith(StringConstants.FORWARD_SLASH)) {