Fix for bug #9128: issue with salt-master ttys with lvdisplay command

lvdisplay checks the file flags of the ttys file descriptors.
Currently all three stds file descriptor are set write only.

This fix :
+ set stdin as read only
+ set stdout, stderr as write only
Updated fix for #9128

Better use 'r+' while opening stdin as recommanded by s0undt3ch
Revert "Updated fix for #9128"

This reverts commit 29f86cbc010600f54e54c10fceb1bb776bf248d5.
Revert "Fix for bug #9128: issue with salt-master ttys with lvdisplay command"

This reverts commit 7ca28147a74d11d03df9e96bc9febe1624c13f2f.
Fix for bug #9128: stdin issue with lvdisplay command

lvm related command breaks while checking the filedescriptor flags.
Setting flags to 'r+' fixes it.

'r+' Open for reading and writing.  The stream is positioned at the
beginning of the file. (cf fopen man page)
Minor typo fixes
Add complete option parsing for Debian network interfaces

Inspired by bond option parsing.

Bridge option checks are based on debian man page:
http://manpages.debian.net/cgi-bin/man.cgi?query=bridge-utils-interfaces