get rid of unnecessary fgets() buffer size limitation

get rid of unnecessary fgets() buffer size limitation

fgets() will read at most size-1 bytes into the buffer and add a
terminating null-char at the end. Therefore it is not necessary to pass
a reduced buffer size when calling it.

This change was generated using the following semantic patch:

@@
identifier buf, fp;
@@
- fgets(buf, sizeof(buf) - 1, fp)
+ fgets(buf, sizeof(buf), fp)

Signed-off-by: Phil Sutter <phil@nwl.cc>