changefile name should not be limited to 256 characters

results in this type of exception:

javax.jdo.JDOFatalUserException: Attempt to store value "/maven/archiva/trunk/archiva-database/src/main/java/org/apache/maven/archiva/database/project/DatabaseProjectModelResolver.java (from /maven/archiva/trunk/archiva-base/archiva-consumers/archiva-database-consumers/src/main/java/org/apache/maven/archiva/consumers/database/project/DatabaseProjectModelResolver.java:547276)" in column ""NAME"" that has maximum length of 256. Please correct your data!