Fix some new errors and a warning in cryptotest.

• Use a new 'char *key' to allocate storage for keys and assign the pointer to the session2_op 'const char *' members after the key is initialized.
• Mark the 'find' variable used in crfind() static so that crfind() doesn't return a pointer to stack garbage.

Reported by: olivier (1)
MFC after: 2 weeks
Sponsored by: Chelsio Communications