[OE-core] [PATCH v2] toolchain-shar-relocate.sh: Add check for missing command 'file'

On a machine without the file command, the SDK install fails with a cryptic error message. ``` xargs: file: No such file or directory sed: no input files Failed to replace perl. Relocate script failed. Abort! ``` Add a test for 'file' to print a clear error message. ``` The command 'file' is

[OE-core] [[PATCH v2]] toolchain-shar-relocate.sh: Add check for missing command 'file'

On a machine without the file command, the SDK install fails with a cryptic error message. ``` xargs: file: No such file or directory sed: no input files Failed to replace perl. Relocate script failed. Abort! ``` Add a test for 'file' to print a clear error message. ``` The command 'file' is