Fixes:
root@turris:~# opkg remove sentinel-i_agree_with_eula
Removing package sentinel-i_agree_with_eula from root...
//usr/lib/opkg/info/sentinel-i_agree_with_eula.prerm: /usr/lib/opkg/info/sentinel-i_agree_with_eula.prerm-pkg: line 10: syntax error: unexpected end of file (expecting "fi")
You can force removal of packages with failed prerm scripts with the option:
	--force-remove
No packages removed.
Collected errors:
 * pkg_run_script: package "sentinel-i_agree_with_eula" prerm script returned status 2.
 * opkg_remove_pkg: not removing package "sentinel-i_agree_with_eula", prerm script failed