fs_mgr: remove the repetitive and annoying bootconfig error print

The new changes to slotselect() call makes it try to find the
"slot" config before trying "slot_suffix" and that causes fs_mgr to
print the needless error and spam the kernel logs for no reason.
Remove the print.

Test: Builds for sailfish

Change-Id: I020575d70f4cd6e137e82c127b5d5234d709d0e3
Signed-off-by: Sandeep Patil <sspatil@google.com>

fs_mgr/fs_mgr_boot_config.cpp

@@ -55,8 +55,6 @@ bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) {
         if (android::base::ReadFileToString(file_name, out_val)) {
             return true;
         }
-
-        LINFO << "Error finding '" << key << "' in device tree";
     }
 
     return false;