fixing infinite loop

if a symlink doesn't start with '/' should consider as relative
debug
git log -1 added to see latest change
end infinite loop if after MaxLoopCounter cycle
test case for following relative symlinks https://github.com/dotcloud/docker/issues/5370

normally symlinks are created as either
```
  ln -s /path/existing /path/new-name
```
or
```
  cd /path && ln -s ./existing new-name
```

but one can create it this way
```
  cd /path && ln -s existing new-name
```

this drives FollowSymlinkInScope into infinite loop