Tpetra: CrsMatrix (not Kokkos refactor yet): Fixed convert.

Thanks to Eric Phipps for pointing out that my recent commit to
Tpetra_CrsMatrix_def.hpp that optimized convert() broke that method.
(The commit only affected the "classic" CrsMatrix, not the Kokkos
refactor version.) In fact, convert() should have returned null
unconditionally.  Does Tpetra have a test for convert()?

This commit fixes the issue.  Note that the Kokkos refactor version of
CrsMatrix::convert() did not have the optimization of the commit in
question, and thus did not share the bug.  I am reluctant to port the
optimization to the Kokkos refactor version until there is a test for
convert().  It should not be hard to write one.

Build/Test Cases Summary
Enabled Packages: Tpetra
0) MPI_DEBUG => passed: passed=72,notpassed=0 (1.63 min)
1) SERIAL_RELEASE => passed: passed=56,notpassed=0 (0.29 min)
Thyra: Updated scalar types so that complex<*> would work

These were failing under SS tests, this fixes those issues

Build/Test Cases Summary
Enabled Packages: ThyraCore
0) MPI_DEBUG => passed: passed=56,notpassed=0 (0.79 min)
1) SERIAL_RELEASE => passed: passed=45,notpassed=0 (5.24 min)
2) MPI_DEBUG_SS => passed: passed=56,notpassed=0 (0.73 min)
3) SERIAL_RELEASE_SS => passed: passed=45,notpassed=0 (4.85 min)
SEACAS: nem_slice - make corrupted mesh warning message more selective to avoid false positives

(From Sierra)
IOSS: Add capability to split hexes into 6 tets in the generated mesh database; specified by "tets" option; does not work yet with sidesets or shell blocks

(From Sierra)

Build/Test Cases Summary
Enabled Packages: SEACASNemslice, SEACASIoss
Disabled Packages: Panzer,PyTrilinos,SEACASExo2mat,SEACASMat2exo
Enabled all Forward Packages
0) MPI_DEBUG => Skipped configure, build, test due to no enabled packages! => Does not affect push readiness! (-1.00 min)
1) SERIAL_RELEASE => Skipped configure, build, test due to no enabled packages! => Does not affect push readiness! (-1.00 min)
2) MPI_DEBUG_SS => passed: passed=21,notpassed=0 (22.79 min)
3) SERIAL_RELEASE_SS => passed: passed=22,notpassed=0 (24.87 min)
Other local commits for this build/test group: 37b0b49
Xpetra: added getExporter to CrsGraph
MueLu: removed dups definitions of minAll and friends
Xpetra: removed sumAll and friends

They were used in very few places, and produced warnings for MueLu.
MueLu: fixed definitions of sumAll and friends

Those definitions included ";" at the end, so they were unusable in
situations like this:
  if (something)
    minAll(something)
  else
     <something>
MueLu: extended matrix stats print outs

Added some communication information from matrix importer, like number
of neighbors, number of sends and receives, ...
MueLu: disabling printing child-parent map in scaling test

Without timers ids the output is useless.
Tpetra: MMM code cleanup
Tpetra: More MMM code cleanup
Tpetra: More MMM comments cleanup
Tpetra: More MMM code cleanup
Tpetra: Updating Import's setUnion
Tpetra: Correcting test

Build/Test Cases Summary
Enabled Packages: Tpetra
Enabled all Forward Packages
0) MPI_DEBUG => passed: passed=653,notpassed=0 (41.51 min)
1) SERIAL_RELEASE => passed: passed=581,notpassed=0 (25.51 min)
2) MPI_DEBUG_SS => passed: passed=1043,notpassed=0 (122.79 min)
Other local commits for this build/test group: 6c8f85d0, bdc7d4a, aed6bd2, 63cb599, 200b304
MueLu: fixing easy interface tests for Macs

Some Macs print outs ptrs as 0x0 instead of 0, search and replace