src/config.c: Bail out on incomplete directive
src/config.c: Bail out on incomplete directive

Fixes a segmentation fault that arose if a line in the configuration
file didn't contain a value/key separator ("="). Instead of operating on
a NULL pointer, throw an error message containing the erroneous
directive and bail out.

Reported-by: Baptiste Jonglez <b0aa5ae32cbebcf8fc6e0ec388d02a4f84ec737b@jonglez.org>
Signed-off-by: Lukas Fleischer <af90e31281d8305af43dc616c5aaca3c7165f8a7@cryptocrack.de>

lfos/calcurse,lfos/calcurse,lfos/calcurse