CDH-18418. Fixing invalid type conversions on some systems.

    Compilation of gperftools fails on some operating systems with a compiler
    error due to an invalid conversion from signinfo_t. gpertools issue #444
    fixes this by using siginfo instead, however on Ubuntu 14.04 this is also
    an invalid conversion, and int appears to be the only type that is a valid
    conversion across all support distros.

    See: https://code.google.com/p/gperftools/issues/detail?id=444

Change-Id: Ie71b4bb8babb4d0403b59973e2ddf5e32f10d12b
(cherry picked from commit 9a677b99b782d8b7dd8fa2391a427936f0a591ac)
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4063
Reviewed-by: Sean Mackrory <sean@cloudera.com>
Tested-by: Sean Mackrory <sean@cloudera.com>