Fixing make

Fixing the following errors during 'make'

`
src/ssl.c:1302:9: error: non-void function 'Java_org_apache_tomcat_jni_SSL_doHandshake' should return a value [-Wreturn-type]
        return;
        ^
src/ssl.c:1316:9: error: non-void function 'Java_org_apache_tomcat_jni_SSL_getNextProtoNegotiated' should return a value [-Wreturn-type]
        return;
        ^
`