Remove GetFilesystemSize.

We don't need to get filesystem size now, because the files passed to
delta_generator is already resized properly.

Also moved Is*Filesystem() to delta_diff_utils.

Test: ./update_engine_unittests
Bug: None

Change-Id: I442d69d1820d08c0f3bd63e7f1986fc4b0d6655e
diff --git a/Android.mk b/Android.mk
index fdfcba7..42617c8 100644
--- a/Android.mk
+++ b/Android.mk
@@ -195,8 +195,7 @@
 LOCAL_CPPFLAGS := $(ue_common_cppflags)
 LOCAL_LDFLAGS := $(ue_common_ldflags)
 LOCAL_C_INCLUDES := \
-    $(ue_common_c_includes) \
-    external/e2fsprogs/lib
+    $(ue_common_c_includes)
 LOCAL_STATIC_LIBRARIES := \
     update_metadata-protos \
     $(ue_libpayload_consumer_exported_static_libraries) \
@@ -219,8 +218,7 @@
 LOCAL_CPPFLAGS := $(ue_common_cppflags)
 LOCAL_LDFLAGS := $(ue_common_ldflags)
 LOCAL_C_INCLUDES := \
-    $(ue_common_c_includes) \
-    external/e2fsprogs/lib
+    $(ue_common_c_includes)
 LOCAL_STATIC_LIBRARIES := \
     update_metadata-protos \
     $(ue_libpayload_consumer_exported_static_libraries:-host=) \