Modify rename_file to fit the pattern of the other file methods.
Otherwise, calling this yields a backtrace in the logs and it fails.
Steps to verify:
rc script:
```
loadpath test/modules
use exploit/multi/handler
set lhost 172.28.128.1
set lport 8081
set payload windows/meterpreter/reverse_http
run -j
sleep 5
resource test/scripts/test-sessions.rc
Before:
```
[-] FAILED: should move files
[-] Exception: TypeError : true is not a symbol
log file:
[01/27/2015 13:17:23] [d(0)] core: Call stack:
/home/bcook/projects/metasploit-framework/lib/msf/core/post/file.rb:357:in
`rename_file'
/home/bcook/projects/metasploit-framework/test/modules/post/test/file.rb:115:in
`block in test_file'
/home/bcook/projects/metasploit-framework/test/lib/module_test.rb:26:in
`call'
/home/bcook/projects/metasploit-framework/test/lib/module_test.rb:26:in
`it'
...
```
After, passing sessions instead:
```
post/test/file
SESSION => 1
Setup: changing working directory to %TEMP%
[*] Running against session 1
[*] Session type is meterpreter and platform is x86/win32
[+] should test for file existence
[+] should test for directory existence
[+] should create text files
[+] should read the text we just wrote
[+] should append text files
[+] should delete text files
[+] should move files
[+] should write binary data
[+] should read the binary data we just wrote
[+] should delete binary files
[+] should append binary data
[*] Passed: 11; Failed: 0
```
Also cleans up some style issues and adds yardoc comments for some stuff
in Post::File
Note that windows/local/service_permissions is still using
`service_list` because it now builds a Rex::Table, which has to have
all the data up front, anyway.
William Vu