Introduce -debugnet option, thereby quieting some redundant debug messages

Prior to this change, each TX typically generated 3+ debug messages,

	askfor tx 8644cc97480ba1537214   0
	sending getdata: tx 8644cc97480ba1537214
	askfor tx 8644cc97480ba1537214   1339640761000000
	askfor tx 8644cc97480ba1537214   1339640881000000
	CTxMemPool::accept() : accepted 8644cc9748 (poolsz 6857)

After this change, there is only one message for each valid TX received

	CTxMemPool::accept() : accepted 22a73c5d8c (poolsz 42)

and two messages for each orphan tx received

	ERROR: FetchInputs() : 673dc195aa mempool Tx prev not found 1e439346fc
	stored orphan tx 673dc195aa (mapsz 19)

The -debugnet option, or its superset -debug, will restore the full debug
output.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/net.h b/src/net.h
index c9c965722e..f059c7a448 100644
--- a/src/net.h
+++ b/src/net.h
@@ -296,7 +296,8 @@ public:
         // We're using mapAskFor as a priority queue,
         // the key is the earliest time the request can be sent
         int64& nRequestTime = mapAlreadyAskedFor[inv];
-        printf("askfor %s   %"PRI64d"\n", inv.ToString().c_str(), nRequestTime);
+        if (fDebugNet)
+            printf("askfor %s   %"PRI64d"\n", inv.ToString().c_str(), nRequestTime);
 
         // Make sure not to reuse time indexes to keep things in the same order
         int64 nNow = (GetTime() - 1) * 1000000;