Add stdout flushing to some tools (#2110)

* add stdout flushing to some tools

* change printb import source in opensnoop tool
diff --git a/tools/tcpconnect.py b/tools/tcpconnect.py
index e1f4461..ddd3fa3 100755
--- a/tools/tcpconnect.py
+++ b/tools/tcpconnect.py
@@ -19,6 +19,7 @@
 
 from __future__ import print_function
 from bcc import BPF
+from bcc.utils import printb
 import argparse
 from socket import inet_ntop, ntohs, AF_INET, AF_INET6
 from struct import pack
@@ -201,7 +202,7 @@
         if start_ts == 0:
             start_ts = event.ts_us
         print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="")
-    print("%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid,
+    printb(b"%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid,
         event.task.decode('utf-8', 'replace'), event.ip,
         inet_ntop(AF_INET, pack("I", event.saddr)),
         inet_ntop(AF_INET, pack("I", event.daddr)), event.dport))
@@ -213,7 +214,7 @@
         if start_ts == 0:
             start_ts = event.ts_us
         print("%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), end="")
-    print("%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid,
+    printb(b"%-6d %-12.12s %-2d %-16s %-16s %-4d" % (event.pid,
         event.task.decode('utf-8', 'replace'), event.ip,
         inet_ntop(AF_INET6, event.saddr), inet_ntop(AF_INET6, event.daddr),
         event.dport))