removed comments about Msg37

Doesn't exist and hasn't existed for several years.

Msg3a.h

@@ -31,7 +31,6 @@ public:
         // . sets errno on error
         // . "query/coll/docIds" should NOT be on the stack in case we block
 	// . uses Query class to parse query
-	// . uses Msg37 to retrieve term frequencies for each termId in query
 	// . uses Indexdb class to intersect the lists to get results
 	// . fills docIds buf with the resulting docIds
 	// . sets *numDocIds to the # of resulting docIds

Msg40.h

@@ -31,7 +31,6 @@ public:
 	// . returns false if blocked, true otherwise
 	// . sets errno on error
 	// . uses Query class to parse query
-	// . uses Msg37 to retrieve term frequencies for each termId in query
 	// . uses Indexdb class to intersect the lists to get results
 	// . fills local buffer, m_docIds, with resulting docIds
 	// . set m_numDocIds to number of docIds in m_docIds

Multicast.h

@@ -68,8 +68,6 @@ class Multicast {
 	//   is false
 	// . Msg40 uses largest termId in winning group as the key to ensure
 	//   that queries with the same largest termId go to the same machine
-	// . likewise, Msg37 uses it to get the term frequency consistently
-	//   so it doesn't jitter
 	// . if you pass in a "replyBuf" we'll store the reply in there
 	// . "doDiskLoadBalancing" is no longer used.
 	bool send ( char       *msg             ,