(buy, check_market, trad, check_trade): Remove the following virtually

undocumented feature: When a buyer didn't have enough money at the
time of the trade, the seller *automatically* granted a high-interest,
medium term loan for up to 90% of the price.  This is just a silly
trap for unwary sellers and buyers alike.
(N_FIN_TROUBLE, N_CREDIT_JUNK): Unused, remove.
(rpt): Update accordingly.

src/lib/global/news.c

@@ -210,10 +210,8 @@ struct rptstr rpt[] = {
 /* 76*/	  	     "naval forces massacred in failed assault of %s" } },
     {-4,  N_FRONT, { "paratroopers destroyed in failed air-assault on %s",
 /* 77*/	  	     "loses parachutists in failed air-assault of %s" } },
-    { 0,  N_ECON,  { "is forced into debt to %s by bad management",
-/* 78*/	  	     "shows bad financial planning" } },
-    { 0,  N_ECON,  { "has its credit rating downgraded to unworthy status",
-/* 79*/	  	     "is denied credit by %s due to lack of collatoral" } },
+/* 78*/ { 0, 0, { no_news, no_news } },
+/* 79*/ { 0, 0, { no_news, no_news } },
     { 0,  N_ECON,  { "is unable to fulfill its financial obligations to %s",
 /* 80*/	  	     "welches on a deal with %s" } },
     { -3, N_FRONT, { "is repelled by %s while attempting to board a land unit",