liblog: remove alarm in logd_reader.cpp

There is an alarm() call that provides a 30 second timeout in case
logd is unavailable.  The main reason for this is in the case that logd
is crashing, debuggerd is ptrace'ing logd, and tombstoned is
attempting to dump log messages.  In this case, with no other checks
and without this alarm, tombstoned will deadlock when dumping log
messages.

However, tombstoned already has two mechanisms to prevent the above
situation from happening:
1) It checks that the thread name that is is dumping is either logd or
   starts with "logd." and skips dumping logs in this case.
2) It does not dump logs if it is running in process for any process.

Calling alarm() or modifying signal handlers from general purpose
libraries is not recommended either, so without a strong reason to
keep this, this change removes it.

This also shortens the liblog.wrap_mode_blocks test time, since the 30
second issue that it ensures does not happen has been fundamentally
removed.

Test: `kill -8 `pidof logd`` succeeds without delay
Test: liblog, logd unit tests
Change-Id: Id8a40544645d220e49f7ba299201af80a0c44de9

0 files changed, 0 insertions, 0 deletions