update_identity: ignore input fpr. _myself: ignore input fpr *earlier*; fix myself header comment

By fdik, attempting to fix QA-176, QA-177, QA-180 and at least implementing
correct behaviour.

There is a change perfectly analogous to this on Release_2.1 (with a mistake in
the commit message: the header comment change is about myself, not about
_update_identity).

src/keymanagement.c

@@ -636,6 +636,11 @@ DYNAMIC_API PEP_STATUS update_identity(
     if (!(session && identity && !EMPTYSTR(identity->address)))
         return PEP_ILLEGAL_VALUE;
 
+    /* The fpr field is output only: in case it was set, unset it before doing
+       anything else. */
+    free(identity->fpr);
+    identity->fpr = NULL;
+
     //
     // Record some information about the input identity so that we don't keep 
     // evaluating it
@@ -1019,6 +1024,13 @@ PEP_STATUS _myself(PEP_SESSION session,
     if (!session || !identity || EMPTYSTR(identity->address))
         return PEP_ILLEGAL_VALUE;
 
+    // ignore input fpr
+
+    if (identity->fpr) {
+        free(identity->fpr);
+        identity->fpr = NULL;
+    }
+
     // this leads to crashes otherwise
 
     if (EMPTYSTR(identity->user_id)) {
@@ -1118,13 +1130,6 @@ PEP_STATUS _myself(PEP_SESSION session,
         }
     }
 
-    // ignore input fpr
-
-    if (identity->fpr) {
-        free(identity->fpr);
-        identity->fpr = NULL;
-    }
-
     // check stored identity
     if (stored_identity) {
         if (!EMPTYSTR(stored_identity->fpr)) {

src/keymanagement.h

@@ -93,10 +93,8 @@ DYNAMIC_API PEP_STATUS update_identity(
  *  @param[in]     session     session to use
  *  @param[in,out] identity    identity of local user
  *                             both .address and .user_id must be set.
- *                             if .fpr is set, an attempt will be made to make
- *                             that the default key for this identity after key
- *                             validation
- *                             if .fpr is not set, key retrieval is performed
+ *                             The .fpr field is output-only, and any value set at
+ *                             input is ignored; it is set by key retrieval.
  *                             If .username is set, it will be used to set or patch
  *                             the username record for this identity.                         
  *