ssl_store_cert(): Declare a variable at the beginning of the the code block

ssl_store_cert(): Declare a variable at the beginning of the the code block

... to silence:

    cc -c -pipe -fstack-protector-all -ggdb -Wshadow  -Wconversion -I/usr/local/include/  -pthread -Wall -std=c89   openssl.c -o openssl.o
    openssl.c:408:12: warning: GCC does not allow variable declarations in for loop initializers before C99 [-Wgcc-compat]
          for (int i = 0; i < bs->length; i++)
               ^