In looking through the RPM that's available from the Dropbox website I only see the following content.
$ rpm -qpl nautilus-dropbox-1.6.0-1.fedora.x86_64.rpm |& \
grep -Ev "/icons/|.icon$|.png$|warning:"
We can unroll the RPM to take a peak at the contents like so:
$ mkdir db_unroll
$ cd db_unroll
$ rpm2cpio ../nautilus-dropbox-1.6.0-1.fedora.x86_64.rpm | cpio -idmv
The only file that looks of interest is the
$ more usr/share/applications/dropbox.desktop
Comment=Sync your files across computers and to the web
Exec=dropbox start -i
So how can I stop it from starting?
You could use a modified version of the technique I outline in this other U&L Q&A titled: Update different dropbox instances, which shows how you can run the Dropbox
dropboxd daemon for multiple dropbox instances. This same approach will work for a single instance and give you a more sanely behaving Dropbox instance.
Removing the RPM?
If nothing else works, I'd uninstall the RPM and install the binary distro instead. The download page has a section titled: "Install Dropbox via command line".