ceph.spec.in: disable annobin plugin if compile with gcc-toolset

ceph.spec.in: disable annobin plugin if compile with gcc-toolset

we are seeing FTBFS failures when compiling the packages with seastar
enabled, like:

Package gcc-toolset-9-annobin-9.08-4.el8.x86_64 is already installed.
...
Package redhat-rpm-config-130-1.el8.noarch is already installed.
...
CFLAGS=-O2 -g -pipe -Wall -Werror=format-security  -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
...
-- The CXX compiler identification is GNU 9.2.1
....
    Building CXX object CMakeFiles/cmTC_386fb.dir/testCXXCompiler.cxx.o
    /opt/rh/gcc-toolset-9/root/usr/bin/c++   -O2 -g -pipe -Wall -Werror=format-security  -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection  -o CMakeFiles/cmTC_386fb.dir/testCXXCompiler.cxx.o -c /home/jenkins-build/build/workspace/ceph-dev-new-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos8/DIST/centos8/MACHINE_SIZE/gigantic/release/17.2.0-209-g3e01cd41/rpm/el8/BUILD/ceph-17.2.0-209-g3e01cd41/x86_64-redhat-linux-gnu/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
    cc1plus: fatal error: inaccessible plugin file /opt/rh/gcc-toolset-9/root/usr/lib/gcc/x86_64-redhat-linux/9/plugin/gcc-annobin.so expanded from short plugin name gcc-annobin: No such file or directory

the root cause is that redhat-rpm-config expects gcc-annobin:

$ cat /usr/lib/rpm/redhat/redhat-annobin-cc1 *cc1_options: + %{!-fno-use-annobin:%{!iplugindir*:%:find-plugindir()} -fplugin=gcc-annobin}

while this plugin is not installed by gcc-toolset-9-annobin, which installs annobin.so though:

$ rpm -ql gcc-toolset-9-annobin| grep annobin.so /opt/rh/gcc-toolset-9/root/usr/lib/gcc/x86_64-redhat-linux/9/plugin/annobin.so /opt/rh/gcc-toolset-9/root/usr/lib/gcc/x86_64-redhat-linux/9/plugin/annobin.so.0 /opt/rh/gcc-toolset-9/root/usr/lib/gcc/x86_64-redhat-linux/9/plugin/annobin.so.0.0.0

but gcc-toolset-8-annobin provides this file. upgrading to
gcc-toolset-11 does not help. see https://centos.pkgs.org/8-stream/centos-appstream-x86_64/gcc-toolset-11-annobin-plugin-gcc-10.23-1.el8.x86_64.rpm.html
so, the intermediate solution would be to disable the plugin, if
we want to use gcc-toolset to build rpm packages.

in this change, _annotated_build is undefined to prevent the compiler
from adding extra information to the binary. in general this change
shuold be safe, without these information, it'd be hard to tell if
the binary is hardened or what ABI version it expects. see
also https://fedoraproject.org/wiki/Changes/Annobin

Signed-off-by: Kefu Chai <tchaikov@gmail.com>