M #-: fix minor bug in S3 upload (#264)

src/datastore_mad/remotes/vcenter/cp

@@ -173,7 +173,7 @@ files_to_upload.each_with_index do |f, index|
     cmd = "#{File.dirname(__FILE__)}/../vcenter_uploader.rb #{uploader_args}"
 
     target, stderr, status = Open3.capture3(cmd)
-  
+
     if !status.success?
         STDERR.puts "Cannot upload file #{f}: #{stderr}"
         FileUtils.rm_rf(temp_file) if temp_file

src/market_mad/remotes/s3/import

@@ -111,10 +111,17 @@ end
 
 cmd = "#{UTILS_PATH}/downloader.sh #{import_source} -"
 
-Open3.popen3(cmd) do |_, o, _, _|
+Open3.popen3(cmd) do |_, o, e, _|
     body = o.read(read_length)
 
     if o.eof?
+        error = Thread.new { e.read }.value
+
+        unless error.empty?
+            STDERR.puts error
+            exit 1
+        end
+
         s3.put_object(body)
     else
         s3.create_multipart_upload

src/vmm_mad/remotes/lib/vcenter_driver/file_helper.rb

@@ -197,7 +197,7 @@ module VCenterDriver
                     .dirname(
                         descriptor_url.host+descriptor_url.path
                     )
-                next unless ds.descriptor?(image_path + '/' + file_to_download)
+                next unless ds.is_descriptor?(image_path + '/' + file_to_download)
 
                 files_to_download <<
                     download_all_filenames_in_descriptor(
@@ -223,7 +223,7 @@ module VCenterDriver
         # related files, creates a tar.gz and dumps it in stdout
         def self.dump_vmdk_tar_gz(vcenter_url, ds)
             image_source = vcenter_url.host + vcenter_url.path
-            if ds.descriptor?(image_source)
+            if ds.is_descriptor?(image_source)
                 files_to_download =
                     get_all_filenames_in_descriptor(
                         vcenter_url,