3rd-party: rename libevent release to stable_ompi

rpmbuild now does not accept '-' in release name.
This patch rebuilds libevent 2.1.12-stable with:
- autoconf 2.27
- automake 1.16.5
- libtool  2.4.7

Note that this libevent release contains ambiguous python shebang that will
cause rpm build failures on modern systems. Read more:
https://fedoraproject.org/wiki/Changes/Make_ambiguous_python_shebangs_error

Signed-off-by: Wenduo Wang <wenduwan@amazon.com>

autogen.pl

@@ -71,7 +71,7 @@
 my $ompi_libtoolize_search = "libtoolize;glibtoolize";
 
 # version of packages we ship as tarballs
-my $libevent_version="2.1.12-stable-ompi";
+my $libevent_version="2.1.12-stable_ompi";
 my $hwloc_version="2.7.1";
 
 # One-time setup