locks: plug warnings about unitialized variables

They only showed up after I redefined LOCKSTAT_ENABLED to 0.

doing_lockprof in mutex.c is a real (but harmless) bug. Should the
value be non-zero it will do checks for lock profiling which would
otherwise be skipped.

state in rwlock.c is a wart from the compiler, the value can't be
used if lock profiling is not enabled.

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