Minor ecdsa cleanups

- point_format is of no use
- d was init'ed and free'd twice
diff --git a/include/polarssl/ecdsa.h b/include/polarssl/ecdsa.h
index e709b40..bc1afbb 100644
--- a/include/polarssl/ecdsa.h
+++ b/include/polarssl/ecdsa.h
@@ -39,7 +39,6 @@
     ecp_point Q;        /*!<  public signature key          */
     mpi r;              /*!<  first integer from signature  */
     mpi s;              /*!<  second integer from signature */
-    int point_format;   /*!<  format for point export       */
 }
 ecdsa_context;
 
diff --git a/library/ecdsa.c b/library/ecdsa.c
index 1074850..e87bc65 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -197,8 +197,6 @@
     ecp_point_init( &ctx->Q );
     mpi_init( &ctx->r );
     mpi_init( &ctx->s );
-    mpi_init( &ctx->d );
-    ctx->point_format = POLARSSL_ECP_PF_UNCOMPRESSED;
 }
 
 /*
@@ -211,8 +209,6 @@
     ecp_point_free( &ctx->Q );
     mpi_free( &ctx->r );
     mpi_free( &ctx->s );
-    mpi_free( &ctx->d );
-    ctx->point_format = POLARSSL_ECP_PF_UNCOMPRESSED;
 }
 
 #if defined(POLARSSL_SELF_TEST)