No it wasnt. The Titanic collided with the iceberg the 14th of April 1912, well 2 years before WWI.
Give it another hundred years and two years becomes "just before WW1" ..

The "submarine" conspiracy theory doesn't strike me as believable for several reasons:
I do not believe that the submarine technology of the time allowed for a European's submarine's operational are to extent to the western north Atlantic.
While there was a lot of sabre rattling going on (there was an effective naval arms race at the time), I do not believe that the overall political situation of the times would have sanctioned such an operation. Submarines, at the time, were also viewed with suspicion, as being "ungentlemanly" and more of a coastal defence weapon.