Make it obvious to 'dumpxml' readers what unit we are using,
since our default of KiB for memory (1024) differs from qemu's
default of MiB; and differs from our use of bytes for storage.

Tests were updated via:

$ find tests/*data tests/*out -name '*.xml' | \
  xargs sed -i 's/<\(memory\|currentMemory\|hard_limit\|soft_limit\|min_guarantee\|swap_hard_limit\)>/<\1 unit='"'KiB'>/"
$ find tests/*data tests/*out -name '*.xml' | \
  xargs sed -i 's/<\(capacity\|allocation\|available\)>/<\1 unit='"'bytes'>/"

followed by a few fixes for the stragglers.

Note that with this patch, the RNG for <memory> still forbids
validation of anything except unit='KiB', since the code silently
ignores the attribute; a later patch will expand <memory> to allow
scaled input in the code and update the RNG to match.

* docs/schemas/basictypes.rng (unit): Add 'bytes'.
(scaledInteger): New define.
* docs/schemas/storagevol.rng (sizing): Use it.
* docs/schemas/storagepool.rng (sizing): Likewise.
* docs/schemas/domaincommon.rng (memoryKBElement): New define; use
for memory elements.
* src/conf/storage_conf.c (virStoragePoolDefFormat)
(virStorageVolDefFormat): Likewise.
* src/conf/domain_conf.h (_virDomainDef): Document unit used
internally.
* src/conf/storage_conf.h (_virStoragePoolDef, _virStorageVolDef):
Likewise.
* tests/*data/*.xml: Update all tests.
* tests/*out/*.xml: Likewise.
* tests/define-dev-segfault: Likewise.
* tests/openvzutilstest.c (testReadNetworkConf): Likewise.
* tests/qemuargv2xmltest.c (blankProblemElements): Likewise.

The most common cause of errors with rhel5-api turn on was missing
"(type ioemu)" in sexpr or its equivalent in XM configuration file. This
happens because the presence of that part in sexpr (or cfg) depends on
xen version the host is running. Let's avoid it by explicitly specifying
interface model which ensures "type ioemu" will always be emitted.

This patch adds

    <model type='e1000'/>

withing the interface element in all affected xml files. And

    (model 'e1000')

to all corresponding sexpr files with similar fix to cfg files. Such
configuration works regardless on Xen version.

  to handle CDRom devices with no device name
* tests/sexpr2xmltest.c tests/xml2sexprtest.c
  tests/sexpr2xmldata/sexpr2xml-no-source-cdrom.sexpr
  tests/sexpr2xmldata/sexpr2xml-no-source-cdrom.xml
  tests/xml2sexprdata/xml2sexpr-no-source-cdrom.sexpr
  tests/xml2sexprdata/xml2sexpr-no-source-cdrom.xml: added regression
  tests for this case based on Nobuhiro Itou test inputs.
Daniel