Merge pull request #183 from spdx/issue179

Remove logging for missing copyright text

Author: goneall

src/main/java/org/spdx/library/model/SpdxItem.java

@@ -111,7 +111,6 @@ public String getCopyrightText() throws InvalidSPDXAnalysisException {
 		if (retval.isPresent()) {
 			return retval.get();
 		} else {
-			logger.warn("Missing required copyright text.  Returning empty string");
 			return "";
 		}
 	}