Replace pg_asprintf() with psprintf().

This eliminates an awkward coding pattern that's also unnecessarily
inconsistent with backend coding.  psprintf() is now the thing to
use everywhere.

src/common/psprintf.c

@@ -167,41 +167,3 @@ pvsnprintf(char *buf, size_t len, const char *fmt, va_list args)
 
 	return len * 2;
 }
-
-
-/*
- * XXX this is going away shortly.
- */
-#ifdef FRONTEND
-int
-pg_asprintf(char **ret, const char *fmt, ...)
-{
-	size_t		len = 128;		/* initial assumption about buffer size */
-
-	for (;;)
-	{
-		char	   *result;
-		va_list		args;
-
-		/*
-		 * Allocate result buffer.	Note that in frontend this maps to malloc
-		 * with exit-on-error.
-		 */
-		result = (char *) palloc(len);
-
-		/* Try to format the data. */
-		va_start(args, fmt);
-		len = pvsnprintf(result, len, fmt, args);
-		va_end(args);
-
-		if (len == 0)
-		{
-			*ret = result;
-			return 0;
-		}
-
-		/* Release buffer and loop around to try again with larger len. */
-		pfree(result);
-	}
-}
-#endif