minijail: Add some stuff to .gitignore

This change adds lcov-related stuff to .gitignore. Also add libseccomp,
since it can be used to debug the compiled seccomp-bpf filters.

Bug: None
Test: make clean && make MODE=profiling tests && git status

Change-Id: Ifb77c37e19ef63985ea56df2e5bb5c68bced2df3
diff --git a/.gitignore b/.gitignore
index f538f37..b500f2a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,15 @@
 *.o
 *.a
 
+# Coverage-related files that appear when building with MODE=profiling.
+*.gcno
+*.gcda
+/lcov-coverage.info
+/lcov-html/
+
+# libseccomp.
+/libseccomp/
+
 # Shared libraries when compiling in-tree.
 *.so