Don't add $(EX_LIBS) to libssl.pc's Libs.private

Since libssl requires libcrypto and libcrypto.pc already has
Libs.private set exactly the same, there's no reason to repeat it in
libssl.pc.
Reviewed-by: NBernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/5134)

Configurations/unix-Makefile.tmpl

@@ -760,7 +760,6 @@ libssl.pc:
 	    echo 'Version: '$(VERSION); \
 	    echo 'Requires.private: libcrypto'; \
 	    echo 'Libs: -L$${libdir} -lssl'; \
-	    echo 'Libs.private: $(EX_LIBS)'; \
 	    echo 'Cflags: -I$${includedir}' ) > libssl.pc
 
 openssl.pc: