libcutils: change klog_level to KLOG_INFO_LEVEL

Some of Android componets e.g. init have migrated to use base/logging to get rid
of klog utilities. However, without explicit initilization, the default
klog_level is set to 3 which masks the logwrap output.
This patch sets default klog_level to KLOG_INFO_LEVEL to make
android_fork_execvp_ext log available.

Bug: 34256270
Test: manual
Change-Id: Ibe74707a92c954053cd0e6828a984fbd72b4acae