Add debug option for syncbase server in syncbase api tests. If the debugsync flag is enabled, the log level for sync package will be set to 5, the logs will be save to files in a new dir under /tmp and each api test will print the directory names that contains the log for servers (s0 and s1)
Add debug option for syncbase server in syncbase api tests.
If the debugsync flag is enabled, the log level for sync package
will be set to 5, the logs will be save to files in a new dir
under /tmp and each api test will print the directory names that
contains the log for servers (s0 and s1)

Usage: jiri go test v.io/v23/syncbase/featuretests --v23.test -v23test-syncbase-debug-args "-vpath=vsync*=5"

Example print out:
2016/01/07 14:55:47 syncbased log dir for s0: /tmp/s0319700254

Change-Id: I5ea570b2333d3e3c21ca2663525653e56eba4ba5

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref