Adresses comments in #2036 - Thanks to Damjan for the review!

radio/src/sdcard.cpp

@@ -166,6 +166,7 @@ const char *fileCopy(const char *filename, const char *srcDir, const char *destD
 
   result = f_open(&dstFile, path, FA_CREATE_ALWAYS | FA_WRITE);
   if (result != FR_OK) {
+    f_close(&srcFile);
     return SDCARD_ERROR(result);
   }
 

radio/src/strhelpers.cpp

@@ -177,7 +177,8 @@ char *strAppend(char *dest, const char *source, int len)
 {
   while ((*dest++ = *source++)) {
     if (--len == 0) {
-      *dest++ = '\0';
+      *dest = '\0';
+      return dest;
     }
   }
   return dest - 1;