Fix Linux build by not closing a null pointer

Fixes:

src/processor/exploitability_linux.cc: In static member function ‘static bool google_breakpad::ExploitabilityLinux::DisassembleBytes(const std::string&, const uint8_t*, unsigned int, char*)’:
src/processor/exploitability_linux.cc:519:11: error: argument 1 null where non-null expected [-Werror=nonnull]
  519 |     fclose(objdump_fp);
      |     ~~~~~~^~~~~~~~~~~~
In file included from /usr/include/c++/13/cstdio:42,
                 from /usr/include/c++/13/ext/string_conversions.h:45,
                 from /usr/include/c++/13/bits/basic_string.h:4097,
                 from /usr/include/c++/13/string:54,
                 from /usr/include/c++/13/bits/locale_classes.h:40,
                 from /usr/include/c++/13/bits/ios_base.h:41,
                 from /usr/include/c++/13/ios:44,
                 from /usr/include/c++/13/ostream:40,
                 from /usr/include/c++/13/iostream:41,
                 from ./src/google_breakpad/processor/minidump.h:88,
                 from ./src/google_breakpad/processor/exploitability.h:44,
                 from ./src/processor/exploitability_linux.h:41,
                 from src/processor/exploitability_linux.cc:37:
/usr/include/stdio.h:183:12: note: in a call to function ‘int fclose(FILE*)’ declared ‘nonnull’
  183 | extern int fclose (FILE *__stream) __nonnull ((1));
      |

Author: illwieckz

src/processor/exploitability_linux.cc

@@ -516,7 +516,6 @@ bool ExploitabilityLinux::DisassembleBytes(const string &architecture,
            raw_bytes_tmpfile);
   FILE *objdump_fp = popen(cmd, "r");
   if (!objdump_fp) {
-    fclose(objdump_fp);
     unlink(raw_bytes_tmpfile);
     BPLOG(ERROR) << "Failed to call objdump.";
     return false;