core: Never free() global_macro.x[MACRO_LOGFILE]

We only assign it from log_file nowadays, so we really shouldn't
ever free it.

We also remove the second pass of test_configured_paths() from
the verification step, as it's completely unnecessary.

Reported-by: Robin Sonefors <rsonefors@op5.com>
Reported-by: Mark Frost <mark.frost1@pepsico.com>
Signed-off-by: Andreas Ericsson <ae@op5.se>
core: Make running Nagios from the path work properly

If nagios is executed as simply 'nagios', we previously used to
fail to locate the executed binary. This patch adds a "search path
for proper program" thing and runs that to locate our own executable
in case we can't find it by normalizing the path used to start it.

Signed-off-by: Andreas Ericsson <ae@op5.se>