camel-lock-helper.c cleanups.

(cherry picked from commit 977410f7f5f66e1f8cef05060912d900ccbdefbb)
Bug 710787 - Replace most uses of sprintf() with g_snprintf()

sprintf() can potentially overwrite the buffer, but g_snprintf() takes
a length to stop it from doing that.

Some of these might instead be replaced by g_strdup_printf().  It is
hard to know if the use of alloca() and sprintf() was just because
g_strdup_printf() did not exist yet, or if alloca() was used for
performance.

(cherry picked from commit ad79ca023cb34175920a0c0fbebf3218f2f4e9eb)

Conflicts:
	camel/camel-certdb.c
Camel: Remove unused db-scrap-tools/db.c

No idea what this was intended for.

Not built, not documented, therefore not needed.

(cherry picked from commit 8c6b78830b9e6a271d83ce46abcb29683ca8e411)