BUILD: select: only declare existing local labels to appease clang

Commit 42a50bd19 ("BUG/MINOR: pollers: remove uneeded free in global
init") removed the 'fail_revt' label from the _do_init() function
in src/ev_select.c but left the local label declaration, which makes
clang unhappy and unable to build.

These labels are only historic and unneeded anyway so let's remove them.

This should be backported where 42a50bd19 is backported.
1 file changed