another mime related exception

[Brian Whitman]

Again a clean build of trunk, getting this from the more indexing  
plugin:

java.util.NoSuchElementException
        at java.util.TreeMap.key(TreeMap.java:1204)
        at java.util.TreeMap.firstKey(TreeMap.java:267)
        at java.util.TreeSet.first(TreeSet.java:377)
	at java.util.Collections$UnmodifiableSortedSet.first(Collections.java: 
1113)
	at  
org 
.apache 
.nutch.indexer.more.MoreIndexingFilter.addType(MoreIndexingFilter.java: 
222)
	at  
org 
.apache 
.nutch.indexer.more.MoreIndexingFilter.filter(MoreIndexingFilter.java: 
91)

Line 222  of MoreIndexingFilter is

    String subType = mimeType.getSubTypes().first().getName();