The previous used .gitignore files were mathing some files that
were actually already in the repository (e.g.,
hostapd/logwatch/hostapd). Avoid this by listing the conflicting
entries in the root directory .gitignore with full path.
This removes need for local configuration to ignore *.o and *~
and allows the src/*/.gitignore files to be removed (subdirectories
will inherit the rules from the root .gitignore).
