gnu: cdparanoia: Disable parallel build.

The build would sometimes fail with errors such as:

make[1]: Entering directory '/tmp/guix-build-cdparanoia-10.2.drv-0/cdparanoia-III-10.2'
gcc -O2 -fsigned-char -g -O2 -c main.c
gcc -O2 -fsigned-char -g -O2 -c report.c
gcc -O2 -fsigned-char -g -O2 -c header.c
gcc -O2 -fsigned-char -g -O2 -c buffering_write.c
gcc -O2 -fsigned-char -g -O2 -c cachetest.c
gcc -O2 -fsigned-char -g -O2 -Wl,-rpath=/gnu/store/h0qhcyf0ci4kb70mmvxn8150rl6d3ykm-cdparanoia-10.2/lib -g -O2 main.o report.o header.o buffering_write.o cachetest.o \
        -L/tmp/guix-build-cdparanoia-10.2.drv-0/cdparanoia-III-10.2/paranoia -L/tmp/guix-build-cdparanoia-10.2.drv-0/cdparanoia-III-10.2/interface \
        -o cdparanoia -lcdda_interface -lcdda_paranoia -lm -lrt
ld: main.o: in function `cleanup':
/tmp/guix-build-cdparanoia-10.2.drv-0/cdparanoia-III-10.2/main.c:667: undefined reference to `paranoia_free'
[...]
collect2: error: ld returned 1 exit status

* gnu/packages/cdrom.scm (cdparanoia)[parallel-build?]: Set to #f.