security/py-python-nss: unbreak after r552532

In file included from src/py_nss.c:341:
src/py_nss.h:126:3: error: typedef redefinition with different types ('struct RSAPublicKey' vs 'struct RSAPublicKeyStr')
} RSAPublicKey;

^

/usr/local/include/nss/blapit.h:281:32: note: previous definition is here
typedef struct RSAPublicKeyStr RSAPublicKey;

^

In file included from src/py_nss.c:341:
src/py_nss.h:136:3: error: typedef redefinition with different types ('struct DSAPublicKey' vs 'struct DSAPublicKeyStr')
} DSAPublicKey;

^

/usr/local/include/nss/blapit.h:323:32: note: previous definition is here
typedef struct DSAPublicKeyStr DSAPublicKey;

^

Reported by: pkg-fallout