Fix compiler warning

The same function iasecc_sm_external_authentication() was declared in
two different .h files.

In file included from ../../src/libopensc/iasecc.h:27:0,
                 from sm-card-iasecc.c:44:
../../src/libopensc/iasecc-sdo.h:324:5: warning: redundant redeclaration of `iasecc_sm_external_authentication' [-Wredundant-decls]
In file included from ../../src/libopensc/opensc.h:44:0,
                 from sm-card-iasecc.c:40:
../../src/libopensc/sm.h:352:5: note: previous declaration of `iasecc_sm_external_authentication' was here
Merge PR#280 from dirkx/master: --no-prompt flag

Add a --no-prompt flag to pkcs15-tool (i.e. the equivalent of the --no-prompt flag of pkcs15-init). As to aid readers with keypads (as commonly used in the medical space).
Merge PR#288 from philipWendland:upstream-ecc-fix

add the possibility to store public ECC keys encoded according to SPKI
EC pubkey storing: Check if params are available before copying.
pkcs15-lib.c / sc_pkcs15init_store_public_key may be called with keyargs->key.u.ec.params.value == NULL. In this case, allocating and copying the parameters will fail. Add a check to prevent this.
pkcs15-dnie: fix compilation when OpenSSL is not used

If OpenSSL is not used then the functions from card-dnie.c are not
defined and in particular dnie_match_card() is not defined.
In that case we use a fake dnie_match_card() that just returns false.
build: disable Secure Messaging if OpenSSL is not used

If OpenSSL is not present or --disable-openssl then Secure Messaging is
disabled.

The problem was that some Secure Messaging code is missing if OpenSSL is
absent. The build/link failed with some missing symbols.

Fix issue #293
Fix compiler warning

pkcs15-dnie.c:242:13: warning: function declaration isn't a prototype [-Wstrict-prototypes]
 const char *sc_driver_version()
             ^
Fix compiler warning

p15card-helper.c:23:5: warning: 'ENABLE_OPENSSL' is not defined, evaluates to 0
      [-Wundef]
    ^
Initial PIN helper
Document options for --pin arguments
Make util_get_pin behave consistent