Correct memory leak in RSA self test

The RSA self test didn't free the RSA context on failure.
diff --git a/library/rsa.c b/library/rsa.c
index 122bc13..c809004 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1772,7 +1772,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( verbose != 0 )
@@ -1786,7 +1787,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( verbose != 0 )
@@ -1799,7 +1801,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )
@@ -1807,7 +1810,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( verbose != 0 )
@@ -1825,7 +1829,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( verbose != 0 )
@@ -1837,7 +1842,8 @@
         if( verbose != 0 )
             mbedtls_printf( "failed\n" );
 
-        return( 1 );
+        ret = 1;
+        goto cleanup;
     }
 
     if( verbose != 0 )