remove hdb ldap create declarations

The hdb_ldap_create and hdb_ldapi_create prototypes use the "static"
keyword, but the functions themselves are not implemented as static.

Heimdal's buildsystem dynamically adds function declarations to
hdb-protos.h based on the actual function implementations. Those
declarations in hdb-protos.h are not declared as static.

Since the build system generates the declarations dynamically, just
remove them from hdb-ldap.c.
Merge pull request #80 from ktdreyer/ldap-declaration

build failure with Fedora regarding hdb_ldap_create and hdb_ldapi_create