virStrToLong* guarantees (via strtol) that the end pointer will be set
to the point at which parsing stopped (even on failure, this point is
the start of the input string).

* src/esx/esx_driver.c (esxGetVersion): Remove pointless
conditional.
* src/qemu/qemu_conf.c (qemuParseCommandLinePCI)
(qemuParseCommandLineUSB, qemuParseCommandLineSmp): Likewise.
* src/qemu/qemu_monitor_text.c
(qemuMonitorTextGetMigrationStatus): Likewise.