Corrupted option file can cause the rocksdb to crash

[NoamRabi20]

When the option file contain characters which are not asci (asci value >127) the "isspace" check will cause to crash

Expected behavior

We should cast all input characters to be unsigned char.

Actual behavior

isspace method (as part of TrimAndRemoveComment) will cause the process to crash.

Steps to reproduce the behavior

fill the option file with characters that their ascii value is more than 127.