clang-tidy: don't assign in if

Found with bugprone-assignment-in-if-condition

Signed-off-by: Rosen Penev <rosenp@gmail.com>

app/actions.cpp

@@ -1290,9 +1290,9 @@ void Modify::delMetadatum(Exiv2::Image* pImage, const ModifyCmd& modifyCmd) {
     }
   }
   if (modifyCmd.metadataId_ == MetadataId::xmp) {
-    Exiv2::XmpData::iterator pos;
     const Exiv2::XmpKey xmpKey(modifyCmd.key_);
-    if ((pos = xmpData.findKey(xmpKey)) != xmpData.end()) {
+    auto pos = xmpData.findKey(xmpKey);
+    if (pos != xmpData.end()) {
       xmpData.eraseFamily(pos);
     }
   }

src/iptc.cpp

@@ -401,8 +401,8 @@ int IptcParser::decode(IptcData& iptcData, const byte* pData, size_t size) {
       pRead += 2;
     }
     if (sizeData <= static_cast<size_t>(pEnd - pRead)) {
-      int rc = 0;
+      int rc = readData(iptcData, dataSet, record, pRead, sizeData);
-      if ((rc = readData(iptcData, dataSet, record, pRead, sizeData)) != 0) {
+      if (rc != 0) {
 #ifndef SUPPRESS_WARNINGS
         EXV_WARNING << "Failed to read IPTC dataset " << IptcKey(dataSet, record) << " (rc = " << rc << "); skipped.\n";
 #endif