Fixed a defect in charset detection.

Author: dnetrebenko-smartling

api-sdk/src/main/java/com/smartling/api/sdk/file/FileApiClientImpl.java

@@ -307,7 +307,7 @@ public FileImportSmartlingData importTranslations(FileImportParameterBuilder fil
     private Charset getCharset(final FileUploadParameterBuilder fileUploadParameterBuilder)
     {
         final String charsetName = fileUploadParameterBuilder.getCharset();
-        return StringUtils.isEmpty(charsetName)?
+        return StringUtils.isNotEmpty(charsetName)?
                 Charset.forName(charsetName) : null;
     }