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)